• Earthquakes and Structures
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• v.4 no.5
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• pp.527-555
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• 2013

This paper proposes probabilistic models for estimating the seismic demands on reinforced concrete (RC) bridges with base isolation. The models consider the shear and deformation demands on the bridge columns and the deformation demand on the isolation devices. An experimental design is used to generate a population of bridges based on the AASHTO LRFD Bridge Design Specifications (AASHTO 2007) and the Caltrans' Seismic Design Criteria (Caltrans 1999). Ground motion records are used for time history analysis of each bridge to develop probabilistic models that are practical and are able to account for the uncertainties and biases in the current, common deterministic model. As application of the developed probabilistic models, a simple method is provided to determine the fragility of bridges. This work facilitates the reliability-based design for this type of bridges and contributes to the transition from limit state design to performance-based design.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.3-5
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• 2002

Breakdown characteristics of a punch-through diode with n+p+p-n+ structure are analyzed with two-dimensional device simulation. Effects of base doping concentration and profile on the breakdown are presented. An analytical expression of a maximum base doping level for the punch-through breakdown is derived. The diode with a linearly graded base doping shows superior leakage current and capacitance is satisfactory for applications for low-voltage circuits.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.141-144
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• 2002

The method of the analysis of the base Gummel number of the PNP BJT(Bipolar Junction Transistor) for integrated circuits based upon the semiconductor physics is proposed and the method of calculating the doping profile of the base region using process conditions is presented. The transistor saturation current obtained from the proposed method of PNP BJT using 20V and 30V process shows an averaged relative error of 6.7% compared with the measured data.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1844-1851
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• 2017

As the capacity of the wireless power transmission increases, a higher supply current which may induce current in nearby conductive parts requires. Induced current may affect electric shock to the human body and malfunction of the electrical equipment. In order to prevent such induced phenomena as a risk factor, shielding is required between the source of the wireless power transmission and the conductive parts. The resonance frequency for the large capacity wireless power transmission has the wavelength of several hundred meters, so most environments are included in the near-field area. By wave impedance, the electric field has higher density in the near-field area and needs to be analyze for protecting. For this purpose, it is necessary to select a substance having a larger electric conductivity and optimized shielding structure. In this paper, an aluminum base shielding structure was presented to conduct experiments on thickness, position, and heat dissipation. In the 35 kW, 60 kHz environments, the optimized 5T Al base shielding structure attenuates the induced current to 43 %.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.948-950
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• 2003

In this literature, the CMOS current mode fout quadrant differentiator circuit is proposed. The implementation is base on an appropriate input stage that converts the input current into a compressed voltage at the input capacitor ($C_{gs}$) of the CMOS driver circuit. This input voltage use as the control output current which flow to the output node by passing through a MOS active load and use it as the feedback voltage to the input node. Simulation results with level 49 CMOS model of MOSIS are given to demonstrate the correct operation of the proposed configuration. But the gain of the circuit is too low so the output differentiate current also low. The proposed differentiator is expected to find several applications in analog signal processing system.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.2
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• pp.232-242
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• 2015

Analytical study of surface recombination at the $Si/SiO_2$ interface is carried out in order to set the optimum surface conditions that result in minimum dark base current and maximum open circuit voltage in silicon solar cells. Recombination centers are assumed to form a continuum rather than to be at a single energy level in the energy gap. It is shown that the presence of a hump in the dark I-V characteristics of high efficiency PERL cells is due to the dark current transition from a high surface recombination regime at low voltage to a low surface recombination regime at high voltage. Successful fitting of reported dark I-V characteristics of a typical PERL cell is obtained with several possible combinations of surface parameters including equal electron and hole capture cross sections.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.871-875
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• 1998

A DSP-based source current control for power conditioner is presented to compensate current harmonics and asymmetries of three-phase four-wire emergency generators caused by nonlinear and/or unbalanced loads. There-phase voltage type converter with split-dc-capacitor is adopted as the power circuit and a new direct source current control method is suggested, which simplifies the controller. The proposed control method shapes the generator current sinusoidally inphase with the voltage and allows the generator to supply maximum power even to single phase loads. An IGBT base lookVA prototype with the controller realized with a DSP (TMS320C32) is built and tested to verify the performance of the power conditioner.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.119-132
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• 1990

To design protection coordination for an electric power distribution system, an expert system is developed, using both the veteran expert's heuristics and the guide book for the distribution facility operation considering feeder configuration, service route, load characteristics fault current and load current. The expert system developed in this papaer determines the type of protective device(clearing current and sequence). The location and rating change of protective device in the old feeder is realized by using old database. Current(T-C) curves of various kinds of protective devices are stored in Knowledge Base (KB). The expert system is developed on a 32 bit personal computer using PROLOG, AutoCAD,dBASEIIIPLUS and FORTRAN. To compute the fault current and loadflow, FORTRAN is used.

• Steel and Composite Structures
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• v.28 no.5
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• pp.559-571
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• 2018

In current engineering practice, circular concrete-filled steel tubular (CFST) columns have been used as effective structural components due to their significant structural and economic benefits. To apply these structural components into steel-concrete composite moment resisting frames, increasing number of research into the column-base connections of circular CFST columns have been found. However, most of the previous research focused on the strength, rigidity and seismic resisting performance of the circular CFST column-base connections. The present paper attempts to investigate the demountability of bolted circular CFST column-base connections using the finite element method. The developed finite element models take into account the effects of material and geometric nonlinearities; the accuracy of proposed models is validated through comparison against independent experimental results. The mechanical performance of CFST column-base connections with both permanent and demountable design details are compared with the developed finite element models. Parametric studies are further carried out to examine the effects of design parameters on the behaviour of demountable circular CFST column-base connections. Moreover, the initial stiffness and moment capacity of such demountable connections are compared with the existing codes of practice. The comparison results indicate that an improved prediction method of the initial stiffness for these connections should be developed.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.287-292
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• 2005

The definitive correction of secondary lip nasal deformities is a great challenge for plastic surgeons. To rectify the secondary lip nasal deformities, various procedures and its modifications have been reported in many centers. However, no universal agreement exist to correct the various components of secondary nasal deformities. The secondary nasal deformity of the unilateral cleft lip has its own characteristic abnormalities including the retroplaced dome of the ipsilateral nasal tip, hooding of the alar rim, a secondary alar-columellar web, short columella, depressed alar base and so forth. Among these components of secondary nasal deformity, maxillary hypoplasia, especially in the area of piriform aperture, and alveolar bone defect can make the alar base depressed, which in turn, leads to wide and flat nasal profile, obtuse nasolabial angle coupled with subnormal nasal tip projection in aspect of aesthetic consideration. Moreover, the maxillary hypoplasia contributes to reduced size of the nasal airway in combination with other component of external nasal deformity and therefore the nasal obstruction may be developed functionally. Therefore, the current authors have performed corrective rhinoplasty with the augmentation of alar base with various methods which include rearrangement of soft tissue, vertical scar tissue flap and use of allogenic or autologous materials in 42 patients between 1998 and 2003. The symmetric alar base could be achieved, which provides the more accurate evaluation and more appropriate management of the various component of any coexisting secondary nasal deformity. In conclusion, the augmentation of alar base, as a single procedure, is a basic and essential to correct the secondary lip nasal deformities.