• Journal of Magnetics
• /
• v.19 no.2
• /
• pp.130-139
• /
• 2014

This paper focuses on the modeling and analysis a novel two-axis rotary normal-stress electromagnetic actuator with compact structure for fast steering mirror (FSM). The actuator has high force density similar to a solenoid, but its torque output is nearly a linear function of both its driving current and rotation angle, showing that the actuator is ideal for FSM. In addition, the actuator is designed with a new cross topology armature and no additional axial force is generated when the actuator works. With flux leakage being involved in the actuator modeling properly, an accurate analytical model of the actuator, which shows the actuator's linear characteristics, is obtained via the commonly used equivalent magnetic circuit method. Finally, numerical simulation is presented to validate the analytical actuator model. It is shown that the analytical results are in a good agreement with the simulation results.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.70-70
• /
• 2003

Active sites and substrate bindings of 1-aminoxyclopropane-1-carboxylate oxidase (MD-ACO1) catalyzing the oxidative conversion of ACC to ethylene have been determined based on site-directed mutagenesis and comparative modeling methods. Molecular modeling based on the crystal structure of Isopenicillin N synthase (IPNS) provided MD-ACO1 structure. MD-ACO1 protein folds into a compact jelly roll shape, consisting of 9 ${\alpha}$-helices, 10 ${\beta}$-strands and several long loops. The MD-ACO1/ACC/Fe(II)/Ascorbate complex conformation was determined from automated docking program, AUTODOCK. The MD-ACO1/Fell complex model was consistent with well known binding motif information (HIS177-ASP179-HIS234). The cosubstrate, ascorbate is placed between iron binding pocket and Arg244 of MD-ACO1 enzyme, supporting the critical role of Arg244 for generating reaction product. These findings are strongly supported by previous biochemical data as well as site-directed mutagenesis data. The structure of enzyme/substrate suggests the structural mechanism for the biochemical role as well as substrate specificity of MD-ACO1 enzyme.

• Steel and Composite Structures
• /
• v.34 no.3
• /
• pp.423-440
• /
• 2020

In the recent years, steel box girder bridges have been extensively used due to high bending stiffness, torsional rigidity, and rapid construction. Therefore, researches related to this girder bridge have been widely conducted. This paper investigates the effect of residual stresses and geometric imperfections on the load-carrying capacity of steel box girder bridges spanning 30 m and 50 m. A three - dimensional finite element model of the steel box girder with a closed section was developed and analyzed using ABAQUS software. Nonlinear inelastic analysis was used to capture the actual response of the girder bridge accurately. Based on the results of analyses, the superimposed mode of webs and flanges was recommended for considering the influence of initial geometric imperfections of the steel box model. In addition, 4% and 16% strength reduction rates on the load - carrying capacity of the perfect structural system were respectively recommended for the girders with compact and non-compact sections, whose designs satisfy the requirements specified in AASHTO LRFD standard. As a consequence, the research results would help designers eliminate the complexity in modeling residual stresses and geometric imperfections when designing the steel box girder bridge.

• Proceedings of the KIEE Conference
• /
• 2009.07a
• /
• pp.1929_1930
• /
• 2009

Fully embedded tunable bandpass filter (BPF) with inductive coupling circuits is newly designed and demonstrated for UHF TV tuner ranged from 500MHz to 900MHz receivers. Conventional RF tuning circuit with an electromagnetic coupled tunable filter has several problems such as large size, high volume, and high cost, since the electromagnetic coupled filter is comprised of several passive components and air core inductors to be assembled and controlled manually. To address these obstacles, compact tunable filter with inductive coupling circuit was embedded into low cost organic package substrate. The embedded filter was optimally designed to have high performance by using high Q spiral stacked inductors, high dielectric $BaTiO_3$ composite MIM capacitors, varactor diodes. It exhibited low insertion loss of approximately -2dB, high return loss of below -10dB, and large tuning range of 56.3%. It has an extremely compact size of $3.4{\times}4.4{\times}0.5mm^3$.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.45 no.2
• /
• pp.1-6
• /
• 2008

A compact analytical model of the threshold voltage for long-channel Asymmetric Double-Gate(ADG) MOSFET is presented. In contrast to the previous models, channel doping and carrier quantization are taken into account. A more compact model is derived by utilizing the potential distribution linearity characteristic of silicon film at threshold. The accuracy of the model is verified by comparisons with numerical simulations for various silicon film thickness, channel doping concentration and oxide thickness.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.1366-1371
• /
• 2008

Four simulation models of plastic plate heat exchangers are designed and simulated. The flat plate type heat exchanger is designed as the reference model in order to evaluate how much thermal performance increases. The turbulence promoter type heat exchanger is fabricated with cylindrical-type vortex generators and rib-type turbulence promoters. The corrugate type is obtained from the conventional stainless steel compact heat exchangers, which are called the herringbone-type compact heat exchangers. The dimple type heat exchanger has a number of dimples on its surface. In this study, the flow and heat transfer characteristics of the plastic plate heat exchanger are investigated using numerical simulation and compared with experimental results. The flows are assumed as a three-dimensional, incompressible and turbulent model. The standard k-$\varepsilon$ model is used as the turbulent flow modeling, the SIMPLE algorithm is used to treat the coupling between pressure and velocity, and first order upwind scheme is used for discretization of momentum, turbulent and energy. The computational analysis and experimental results both show that the friction coefficient and Nu number is highest in the corrugate type.

• KIEE International Transactions on Power Engineering
• /
• v.3A no.2
• /
• pp.63-69
• /
• 2003

The necessity of compact high temperature superconducting cables is more keenly felt in densely populated metropolitan areas. Because the compact high-temperature superconducting cables can be installed in ducts and tunnels, thereby reducing construction costs and making the use of underground space more effective, the effect of introducing it to the power system will be huge. Seoul, Korea, is selected as a review model for this paper. The loads are estimated by scenario based on a survey and analysis of 345kV and 154kV power supply networks in this area. Based on this, the following elements for an urban transmission system are examined. (1) A method of constructing a model system to introduce high-temperature superconducting cables to metropolitan areas is presented. (2) A case study is conducted through the analysis of power demand scenarios, and the amount of high-temperature superconducting cable to be introduced by scenario is examined. (3) The economy involved in expanding existing cables and introducing high-temperature superconducting cables(ducts or tunnels) following load increase in urban areas is examined and compared., and standards for current cable ducts are calculated. (4) The voltage level that can be accommodated by existing ducts is examined.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.40 no.4
• /
• pp.1-12
• /
• 2003

In this study, a regime where independent treatment of SETs in transient simulations is valid has been identified quantitatively. It is found that as in the steady-state case, each SET can be treated independently even in the transient case when the interconnection capacitance is large enough. However, the value of the load capacitance $C_{L}$of the interconnections for the independent treatment of SETs is approximately 10 times larger than that of the steady state case. A compact SET transient model is developed for transient circuit simulation by SPICE. The developed model is based on a linearized equivalent circuit and the solution of master equation is done by the programming capabilities of the SmartSpice. Exact delineation of several simulation time scales and the physics-based compact model make it possible to accurately simulate hybrid circuits in the time scales down to several tens of pico seconds. The simulation time is also shown to depend on the complexity level of the transient model.l.

• International Journal of Highway Engineering
• /
• v.8 no.1 s.27
• /
• pp.139-152
• /
• 2006

Many experimental and numerical approaches have been developed to evaluate paving materials and to predict pavement response and distress. Micromechanical simulation modeling is a technology that can reduce the number of physical tests required in material formulation and design and that can provide more details, e.g., the internal stress and strain state, and energy evolution and dissipation in simulated specimens with realistic microstructural features. A clustered distinct element modeling (DEM) approach was implemented In the two-dimensional particle flow software package (PFC-2D) to study the complex behavior observed in asphalt mixture fracturing. The relationship between continuous and discontinuous material properties was defined based on the potential energy approach. The theoretical relationship was validated with the uniform axial compression and cantilever beam model using two-dimensional plane strain and plane stress models. A bilinear cohesive displacement-softening model was implemented as an intrinsic interface and applied for both homogeneous and heterogeneous fracture modeling in order to simulate behavior in the fracture process zone and to simulate crack propagation. A disk-shaped compact tension test (DC(T)) with heterogeneous microstructure was simulated and compared with the experimental fracture test results to study Mode I fracture. The realistic arbitrary crack propagation including crack deflection, microcracking, crack face sliding, crack branching, and crack tip blunting could be represented in the fracture models. This micromechanical modeling approach represents the early developmental stages towards a 'virtual asphalt laboratory,' where simulations of laboratory tests and eventually field response and distress predictions can be made to enhance our understanding of pavement distress mechanisms, such its thermal fracture, reflective cracking, and fatigue crack growth.

• The KIPS Transactions:PartC
• /
• v.8C no.1
• /
• pp.97-104
• /
• 2001

In this paper, we present a new hierarchical model for performance analysis of channel allocation and packet service protocol in wireless n network. The proposed hierarchical model consists of two parts : upper and lower layer models. The upper layer model is the structure state model representing the state of the channel allocation and call service. The lower layer model, which captures the performance of the system within a given structure state, is the wireless packet retransmission protocol model. These models are developed using SRN which is an modeling tool. SRN, an extension of stochastic Petri net, provides compact modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. Fixed point iteration is used to determine the model parameters that are not available directly as input. That is, the call service time of the upper model can be obtained by packet delay in the lower model, and the packet generation rates of the lower model come from call generation rates of the upper model.