• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.6
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• pp.263-267
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• 2004

A new type of interaction circuitry for a broadband gyro-TWT is presented in this paper. A method for the analysis of dispersion characteristics of a periodic structure, which is composed of conducting posts in a rectangular waveguide, is presented. This method utilizes a mode matching technique and equivalent circuit model. The calculated and measured results demonstrate that this periodic structure could be utilized for the interaction circuit of a wide band Gyro-TWT.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.279-286
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• 1997

The objective of this paper is to investigate the effects of the rocking motion and the vertical natural frequency of a seismically isolated structure using LRBs. The governing equations of motion of the rigid body structure, which consider a large rocking motion, are derived. For the mathematical model of LRB, the horizontal stiffness equation based on Haringx's theory is used. From this paper, as decreasing the vertical natural frequency, the rocking responses increase and the horizontal isolation frequency and its earthquake responses are severely affected.

• The Journal of Industrial Distribution & Business
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• v.6 no.4
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• pp.27-37
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• 2015

Purpose - This study first explores the possible dynamic relationship between ownership structure and firm performance using a panel of 4,900 Chinese-listed small- and medium-sized enterprises (SMEs) from 1999 to 2012. Research design, data, and methodology - We address this issue through a dynamic panel model using a method of moments (GMM) technique and dynamic simultaneous equations to alleviate the potential endogenous problem: unobserved heterogeneity, simultaneity, and dynamic endogeneity. Results - Under the framework of dynamic endogeneity, firm performance has a significantly positive influence on ownership, but not vice versa. Ownership and performance can be explained by their owned lagged values, respectively. Moreover, intertemporal endogeneity exists among ownership, investment, and performance through the application of system dynamic equations, which implies that the relationship among ownership structure, investment, and firm performance is dynamic by nature. Conclusions - This study also significantly contributes to a better understanding of dynamic corporate governance by providing further empirical evidence from the largest capital market in the Asian region.

• Journal of the Korean Society of Safety
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• v.11 no.4
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• pp.16-23
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• 1996

In controlling manipulators interacting with the external environment, an important role is played by the Force/Torque(F/T) sensors. Recently, a number of structures for F/T sensors have been proposed, and some criteria for their evaluation have been introduced. This paper presents a systematic analysis of F/T sensor at the design stage. A model of the F/T sensors, based on Stewart Platform structure, is developed on the basis of static and kinematic equation. The condition number defined by the kinematic velocity and force analysis of F/T sensor is used as a performance Index. Thus, 4 optimal structure factors of 6 D.O. F. F/T sensor are determined by using the condition number.

• Journal of the Society of Naval Architects of Korea
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• v.34 no.1
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• pp.77-86
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• 1997

The advanced development in many fields of engineering and science has caused much interests and demands for crashworthiness and non-linear dynamic transient analysis of structure response. Crash and impact problems have a dominant characteristic of large deformation with material plasticity for short time scales. The structural material shows strain rate-dependent behaviors in those cases. Conventional rate-independent constitutive equations used in the general purposed finite analysis programs are inadequate for dynamic finite strain problems. In this paper, a rate-dependent constitutive equation for elastic-plastic material is developed. The plastic stretch rate is modeled based on slip model with dislocation velocity and its density so that there is neither yielding condition, nor loading conditions. Non-linear hardening rule is also introduced for finite strain. Material constants of present constitutive equation are determined by experimental data of mild steel, and the constitutive equation is applied to uniaxile tension loading.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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• pp.8-17
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• 2015

In this research, low fidelity air/heat load analysis was conducted for the intake of high speed vehicle. For air/heat load calculations, aerodynamic properties at the surface and the boundary layer edge were estimated using Taylor-Maccoll equation for conical flow, shockwave relation and Prandtl-Meyer expansion equation for internal and external flow. Couette flow assumption and Reynolds analogy were used in order to calculate convective heat transfer coefficient. In order to calculate skin friction coefficient for heat transfer coefficient analysis, Van Driest method II and Reference Enthalpy method were considered. An axis symmetric SCRAMJET model was selected as a reference configuration for verifying the proper implementation of the present method. Comparison of the results using the present method and Computational Fluid Dynamic analysis showed that the present method is valuable for efficiently providing pressure and heat loads for air-intake structure design of the high speed air vehicle.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.23-34
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• 1998

A dynamic fluid-structure-soil interaction analysis method is developed to investigate the effects of translational and/or rocking motions on the seismic response of flexible rectangular liquid storage tanks founded on the deformable ground. The governing equation for the dynamics of 3-D rectangular tanks subjected to the translational and/or rocking motion is abtained by applying Rayleigh-Ritz method. The dynamic stiffness matrices of a rigid rectangular foundation resting on the surface of a stratum overlaid bedrock are calculated by hyperelement method. The seismic responses of 3-D flexible tank model founded on the deformable ground is calculated by combining the governing equation for the fluid-tank system with the dynamic stiffness matrix of th rigid surface foundation.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.1
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• pp.781-790
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• 2021

The purpose of this study is to test empirically the effect of Islamic business ethics and market conditions on organizational performance in state-owned construction companies in Indonesia. Data collection in this study was conducted online and the total number of data used was 81 respondents, both directors, heads of departments, and managers (general and project). This study uses a partial least squares structural equation model (PLS-SEM) with a quantitative approach that aims to test hypotheses and relationships between variables, such as Islamic business ethics, market conditions, project management, organizational culture, competitive strategy, and organizational performance. This study shows Islamic business ethics has a significant direct effect on organizational performance. Market conditions do not have a direct significant effect on organizational performance. Meanwhile, the mediating variables of project management and competitive strategy have a significant direct effect on organizational performance. Organizational culture does not have a significant influence on organizational performance. Conversely, market conditions have a significant influence through the mediating variables of project management and competitive strategy on organizational performance. Besides, this study is an attempt to determine the impact of the criteria factors affecting the measurement of the performance of construction organizations in Indonesia in terms of the external environment and organizational structure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1599-1604
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• 2008

In this paper, it has been analyzed how transport characteristics is influenced on gate oxide properties in the subthreshold region as nano structure FinFET is fabricated. The analytical model is used to derive transport model, and Possion equation is used to obtain analytical model. The thermionic emission and tunneling current to have an influence on subthreshold current conduction are analyzed for nano-structure FinFET, and subthreshold swings of this paper are compared with those of two dimensional simulation to verify this model. As a result, transport model presented in this paper is good agreement with two dimensional simulation model, and this study shows that the transport characteristics have been changed by gate oxide properties. As gate length becomes smaller, funneling characteristics, one of the most important transport mechanism, have been analyzed.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2113-2118
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• 2007

In this study, a mathematical model for a thermal analysis of a flat heat pipe with a grooved wick structure is presented. The effects of the liquid-vapor interfacial shear stress, the contact angle, and the amount of liquid charge have been included in the proposed model. In particular, the axial variations of the wall temperature and the evaporation/condensation rates are considered by solving the one-dimensional conduction and the augmented Young-Laplace equations, respectively. In order to verify the model, the results obtained from the model are compared to existing experimental data.