• Journal of Periodontal and Implant Science
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• v.42 no.6
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• pp.196-203
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• 2012

Purpose: The aim of this study was to evaluate the clinical efficiency of the subepithelial connective tissue graft (SCTG) with and without plasma rich in growth factor (PRGF) in the treatment of gingival recessions. Methods: Twenty bilateral buccal gingival Miller's Class I and II recessions were selected. Ten of the recessions were treated with SCTG and PRGF (test group). The rest ten of the recessions were treated with SCTG (control group). The clinical parameters including recession depth (RD), percentage of root coverage (RC), mucogingival junction (MGJ) position, clinical attachment level (CAL), and probing depth (PD) were measured at the baseline, and 1 and 3 months later. The data were analyzed using the Wilcoxon signed rank and Mann-Whitney U tests. Results: After 3 months, both groups showed a significant improvement in all of the mentioned criteria except PD. Although the amount of improvement was better in the SCTG+PRGF group than the SCTG only group, this difference was not statistically significant. The mean RC was $70.85{\pm}12.57$ in the test group and $75.83{\pm}24.68$ in the control group. Conclusions: Both SCTG+PRGF and SCTG only result in favorable clinical outcomes, but the added benefit of PRGF is not evident.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.605-608
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• 1993

Breakdown characteristics of a small rod-to-rod microairgap has been studied for obtain an optimum breakdown voltage and an airgap spacing to be used as an emission control means by the electrical arc-burning unburnt carbon particulates exhausted from a power station burner. It is found that the breakdown voltage at the rod-to-rod airgap spacing in the rang of $1{\sim}100{\mu}m$ decreased with decrease in the rod-to-rod airgap spacing. And there were no minimum breakdown voltage on a $V_b$-Pd characteristics which is known as the minimum voltage in Paschen's law in air atmosphere. Breakdown voltages of the airgap at the constant airgap spacing were $V_{b-dc}>V_{b-ac}>V_{b-pulse}$, and it was lowest for the pulse voltage applied. As a result, it is found that a pulse power was one of effective power compared with dc or ac to be used as such an unburnt carbon particulate emission control means and the airgap spacing became to several tens ${\mu}m$, then the breakdown voltages were down to several handreds voltages.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.66-72
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• 2004

PID control has been well used for several decades. For PID algorithms, some tuning methods are used for selecting PID parameters and with these selected parameters, PID control system is designed. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that the designed control system meets the some specifications. For 2 DOF PID controller design this paper presents a linear combinational type of performance indices constituting of index for robust performance, which is obtained by h infinity norm of a weighted complementary sensitivity function, including other time domain indices such as error, energy and changing rate of control input. By numerical methods, the optimal 2 DOF PID parameters are obtained. Therefore various types of 2 degree of freedom PID controllers such as I-PD controller are used so that this two degree of freedom PID controllers may give more desirable output characteristics. Simulations are done with MATLAB m file and mdl files.

• ETRI Journal
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• v.32 no.2
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• pp.327-329
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• 2010

A fully integrated small form-factor HBT power amplifier (PA) was developed for UMTS Tx applications. For practical use, the PA was implemented with a well configured bottom dimension, and a CMOS control IC was added to enable/disable the HBT PA. By using helix-on-pad integrated passive device output matching, a chip-stacking technique in the assembly of the CMOS IC, and embedding of the bulky inductive lines in a multilayer substrate, the module size was greatly reduced to 2 mm ${\times}$ 2.2 mm. A stage-bypass technique was used to enhance the efficiency of the PA. The PA showed a low idle current of about 20 mA and a PAE of about15% at an output power of 16 dBm, while showing good linearity over the entire operating power range.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.92.1-92.1
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• 2013

Molecular electronics has been the subject of intese research for many years because of the fundamental interest in molecular charge transport and potential applications, such as (bio)nanosensors and molecular memory devices. Molecular electronics requires a method for making reliable eletrical contacts to singlemolecules. To date, several approaches have been reported: scanning-probe microscopy, mechanical break junctions, nano patterning, and direct deposition of electrode on a self-assembled monolayers. However, most methods are laborious and difficult for large-scale application and more importantly, cannot control the number of moleucles in the junction. Recently, DNA has been used as a template for metallic nanostructures (e.g., Ag, Pd, and Au nanowires) through DNA metallization process. Furthermore, oligodeoxynucleotides have been tethered to organic molecules by using conventional organic reactions. Collectively, these techniques should provide an efficient route toward reliable and reproducible molecular electronic devices with large-scale fabrication. Therefore, I will present a paradigm for the fabrication of moleuclar electronic devices by using micrometer-sized DNA-singe organic molecule and DNA triblock structures.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.3
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• pp.323-328
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• 2014

Recently, there has been demand for the convergence of IT (Information and communication Technologies, ICT) with defense, as has already been achieved in civilian fields such as healthcare and construction. It is expected that completely new and common requirements would emerge from the civilian and military domains and that the shape of war field would change rapidly. Many military scientists forecast that future wars would be network-centric and be based on C4I(Command, Control, Communication & Computer, Intelligence), ISR(Intelligence, Surveillance & Reconnaissance), and PGM(Precision Guided Munitions). For realizing the smart defense concept, IT should act as a baseline technology even for simulating a real combat field using virtual reality. In this paper, we propose the concept of IT-based smart defense with a focus on accurate detection in real and cyber wars, effective data communication, automated and unmanned operation, and modeling and simulation.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.369-375
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• 1997

$V_{2}O_{5}/ThO_{2}/Pd$-doped $SnO_{2}$ sensor has a good selectivity and stability to CO at high sensor temperature of about $500^{\circ}C$, and shows rapid response. In particular, many kinds of interference gases, such as $NO_{x}$, $C_{3}H_{8}$, $CH_{4}$ and $SO_{2}$ have been found to give only a slight influence on the sensor selectivity to CO gas sensitivity by doped $V_{2}O_{5}$ (3.0 wt.%). For the sensor we used well-known thick film technological route with $V_{2}O_{5}$(3.0 wt.%), Pd(1.0 wt.%) and $ThO_{2}$(l.5 wt.%) as catalytic materials. In the case of mixed $NO_{x}$-CO gases, as combustion exhaust gas, only CO detection by $SnO_{2}$ type semiconductor sensor is generally very difficult because of $NO_{x}$ interference. The developed sensors can use to measure the exhausting gas of the automobile or the boiler for the Air-to-Fuel ratio control.

• ETRI Journal
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• v.31 no.6
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• pp.770-777
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• 2009

We have developed a fully functional reconfigurable optical add-drop multiplexer (ROADM) switch module using a polymer integrated photonic lightwave circuit technology. The polymer variable optical attenuator (VOA) array and digital optical switch array are integrated into one polymer PLC chip and packaged to form a 10-channel VOA integrated optical switch module. Four of these optical switch modules are used in the ROADM switch module to execute 40-channel switching and power equalization. As a wavelength division multiplexer (WDM) filter device, two C-band 40-channel athermal arrayed waveguide grating WDMs are used in the ROADM module. Optical power monitoring of each channel is carried out using a 5% tap PD. A controller and firmware having the functions of a 40-channel switch and VOA control, optical power monitoring, as well as TEC temperature control, and data communication interfaces are also developed in this study.

• The Journal of Internal Korean Medicine
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• v.31 no.2
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• pp.254-263
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• 2010

Objectives : The neuroprotective effects of bee venom (BV) have been demonstrated in many studies, but bee venom has many side effects. So we used sweet bee venom (SBV), which has high molecular elements removed to reduce the side effects. I examined the neuroprotective effect of sweet bee venom in 1-methyl-4-phenylpyridine ($MPP^+$)-induced human neuroblastoma SH-SY5Y cells. Methods : To observe the possible toxicity of SBV itself, SH-SY5Y cells were treated with SBV in various concentrations for 3 h and $MPP^+$ in concentrations (1 and 5mM) for 24h. To investigate the protective effect of SBV against $MPP^+$ toxicity, SH-SY5Y cells were pretreated with vehicle or nontoxic concentrations of SBV for 3h and the cells were not washed, followed by incubation with respective concentrations of SBV and 1 mM $MPP^+$ for 24h. To investigate the protective effect of SBV against $MPP^+$ toxicity, SH-SY5Y cells were pretreated with vehicle or nontoxic concentrations of SBV for 3h and the cells were not washed, followed by incubation with respective of SBV(0.5%), 1 mM $MPP^+$, 5uM AKT inhibitor(LY984002) and 10uM ERK inhibitor(PD98059) for 24 h. The protective effect was measured by cell viability assay. To investigate the degree of apoptosis, caspase-3 enzyme activity was measured in control, $MPP^+$, SBV+$MPP^+$. Results : SBV (0.5%) pretreatment protected the SH-SY5Y cells against $MPP^+$-induced apoptotic cell death. The cell viability was higher in the SH-SY5Y cells that were pretreated with vehicle or nontoxic concentrations of SBV than those not pretreated. The caspase-3 activity was lower in the pretreated groups than these not pretreated. ERK and AKT enzymes have a role in the neuroprotective effects of the sweet bee venom. Conclusions : The results demonstrate that SBV has a protective effect on dopaminergic neurons against $MPP^+$ toxicity. This data suggest that SBV could be a potential therapeutic tool for neurodegenerative diseases such as Parkinson's disease(PD).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.4
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• pp.11-17
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• 2001

In this paper, we propose a polarity decision carrier recovery algorithm for high order QAM(Quadrature Amplitude Modulation), which has robust and large frequency acquisition performance in the high order QAM modem. The proposed polarity decision PD(Phase Detector) output and its variance characteristic are mathematically derived and the simulation results are compared with conventional DD(Decision-Directed) method. While the conventional DD algorithm has linear range of $3.5^{\circ}{\sim}3.5^{\circ}$, the proposed polarity decision PD algorithm has linear range as large as $-36^{\circ}{\sim}36^{\circ}$ at ${\gamma}-17.9$. The conventional DD algorithm can only acquire offsets less than ${\pm}10\;KHz$ in the case of the 256 QAM while an analog front-end circuit generally can reduce the carrier-frequency offset down to only ${\pm}100\;KHz$. Thus, in this case additional AFC or phase detection circuit for carrier recovery is required. But by adopting the proposed polarity decision algorithm, we can find the system can acquire up to ${\pm}300\;KHz$at SNR = 30dB without aided circuit.