• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.2
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• pp.83-87
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• 2004

Phase noise performance and current consumption of Radio Frequency (RF) Voltage-Controlled Oscillator (VCO) are largely dependent on the Quality (Q) factor of inductor-capacitor (LC) tank. Because the Q-factor of LC tank is determined by on-chip spiral inductor, we designed, analyzed, and modeled on-chip differential inductor to enhance differential Q-factor, reduce current consumption and save silicon area. The simulated inductance is 3.3 nH and Q-factor is 15 at 2 GHz. Self-resonance frequency is as high as 13 GHz. To verify its use to RF applications, we designed 2 GHz differential LC VCO. The measurement result of phase noise is -112 dBc/Hz at an offset frequency of 100 kHz from a 2GHz carrier frequency. Tuning range is about 500 MHz (25%), and current consumption varies from 5mA to 8.4 mA using bias control technique. Implemented in $0.35-{\mu}m$ SiGe BiCMOS technology, the VCO occupies $400\;um{\times}800\;um$ of silicon area.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.7
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• pp.508-516
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• 1998

Mo-tip field emitter arrays(FEAs) were fabricated by conventional Spindt process and their life time characteristics and failure mode were evaluated. The fabricated Mo-tip FEA could generate at least $0.35\{mu} A/tip$ emission current for about 320 persistently under a constant gate bias of 140 V and was finally destroyed through self-healing mode. Thin diamond-like carbon films were coated on the M-tip by plasma-enhanced CVD and the dependence of emission properties upon the DLC thickness was investigated. By DLC coating, the turn-on voltage and emission current were appeared to be improved whereas the current fluctuation was increased in the DLC thickness range of $0~1,000\{AA}$.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2949-2952
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• 2000

A new neural networks and learning algorithm are proposed in order to measure nonlinear heights of complexed road environments in realtime without pre-information. This new neural networks is Error Self Recurrent Neural Networks(ESRN), The structure of it is similar to recurrent neural networks: a delayed output as the input and a delayed error between the output of plant and neural networks as a bias input. In addition, we compute the desired value of hidden layer by an optimal method instead of transfering desired values by back-propagation and each weights are updated by RLS(Recursive Least Square). Consequently. this neural networks are not sensitive to initial weights and a learning rate, and have a faster convergence rate than conventional neural networks. We can estimate nonlinear models in realtime by ESRN and learning algorithm and control nonlinear models. To show the performance of this one. we control 7 degree of freedom full car model with several control method. From this simulation. this estimation and controller were proved to be effective to the measurements of nonlinear road environment systems.

• Korean Journal of Biological Psychiatry
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• v.13 no.4
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• pp.226-233
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• 2006

Depression is one of the most common mental disorders. Some characteristics of depression in Korea were elucidated. The tendency to express depressive feeling through somatic complaints is more prominent in Korea than in Western countries. Careful studies on depressive symptoms suggest that guilt and suicidal idea are apparent among Korean depressive patients as well as among Western subjects. But most depressive patients in Korea are reluctant to express suicidal idea, which is hidden under the somatic complaints. We should remember the possibility of research artifacts or cultural bias with regard to the evaluation of depressive symptoms of a country in comparison with other countries. Non-pharmacological treatment of depression includes dynamic psychotherapy, cognitive behavioral therapy, interpersonal psychotherapy, self-care treatment, etc. Some kinds of Korean culture relevant psychotherapies are introduced: Tea therapy, Imago therapy, Tao psychotherapy, and combined approach. Interest in the aged people is growing recently, and the research about the factors which affect the depressive disorders in older patients and treatment strategy for them is ongoing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.1
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• pp.67-76
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• 2000

In this paper, a low noise amplifier has been developed, which is operating at L-band i.e., 1525-1575 MHz. By using resistive decoupling circuits, the resistor dissipates undesired signal in low frequency band. By adopting this design method the stability of the LNA is increased and the input impedance matching is improved. The LNA consists of the low noise GaAs FET ATF-10136 and the internally matched VNA-25. The low LNA is fabricated by both the RP circuit and the self-bias circuits in an aluminum housing. As a result, the characteristics of the LNA implemented show more than 32 dB in gain, lower than 0.5 dB in noise figure, 18.6 dBm output gain in 1 dB gain compression point.

• Journal of Korean society of Dental Hygiene
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• v.20 no.3
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• pp.257-268
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• 2020

Objectives: This purpose of this study was to examine the trends in interventional research and analyze the contents and results of intervention through a systematic literature review of the domestic research literature, suggesting the effect of an oral care program on elementary school students. Methods: A total of 262 articles were retrieved initially, and the duplicate articles were then removed, excluded after screening titles, abstracts, and full-text articles. Finally, a total of 16 papers were used in the review. Results: The study included 9 articles with the nonequivalent control group pretest-posttest design and 7 with the one-group pretest-posttest design. All articles were of non-randomized studies. The most common index of the interventional effect was dental plaque. Further, oral health behaviors and knowledge, perception, self-efficacy, and DMFT index were common indices. In the quality assessment, in the "blinding of outcome assessment" among six items of ROBANS, 12 studies showed a high risk of bias. Conclusions: In order to develop an interventional oral health care program for elementary school students and evaluate the effectiveness, a strict research design and qualitative improvement of research reports are required, and continuous research should be conducted to develop a systematic protocol.

• Journal of the Korean Vacuum Society
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• v.9 no.1
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• pp.7-15
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• 2000

An ECR-PECVD system with the characteristics of high ionization rat다 ability of plasma processing in a wide pressure range and deposition at low temperature was manufactured and characterized for the deposition of thin films. The system consists of a vacuum chamber, sample stage, vacuum gauge, vacuum pump, gas injection part, vacuum sealing valve, ECR source and a control part. The control of system is carried out by the microprocessor and the ROM program. We have investigated the vacuum characteristics of ECR-PECVD system, and also have diagnosed the characteristics of ECR microwave plasma by using the Langmuir probe. From the data of system and plasma characterization, we could confirmed the stability of pressure in the vacuum chamber according to the variation of gas flow rate and the effect of ion bombardment by the negative DC self bias voltage. The plasma density was increased with the increase of gas flow rate and ECR power. On the other hand, it was decreased with the increase of horizontal radius and distance between ECR source and probe. The calculated plasma densities were in the range of 49.7\times10^{11}\sim3.7\times10^{12}\textrm{cm}^{-3}$. It is also expected that we can estimate the thickness uniformity of film fabricated by the ECR-PECVD system from the distribution of the plasma density.

• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.237-242
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• 2018

We report on the fabrication and photoelectrochemical (PEC) properties of a ZnO nanorod array structure as an efficient photoelectrode for hydrogen production from sunlight-driven water splitting. Vertically aligned ZnO nanorods were grown on an indium-tin-oxide-coated glass substrate via seed-mediated hydrothermal synthesis method with the use of a ZnO nanoparticle seed layer, which was formed by thermally oxidizing a sputtered Zn metal thin film. The structural and morphological properties of the synthesized ZnO nanorods were examined using X-ray diffraction and scanning electron microscopy, as well as Raman scattering. The PEC properties of the fabricated ZnO nanorod photoelectrode were evaluated by photocurrent conversion efficiency measurements under white light illumination. From the observed PEC current density versus voltage (J-V) behavior, the vertically aligned ZnO nanorod photoelectrode was found to exhibit a negligible dark current and high photocurrent density, e.g., $0.65mA/cm^2$ at 0.8 V vs Ag/AgCl in a 1 mM $Na_2SO_4$ electrolyte. In particular, a significant PEC performance was observed even at an applied bias of 0 V vs Ag/AgCl, which made the device self-powered.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.1091-1097
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• 2021

The purpose of this research was to investigate the relationship between employee engagement and individual performance outcomes (including growth, achievement, contribution, and customer satisfaction) in large firms in Thailand, which is rapidly growing as an international business hub. The study took place in Thai offices of multinational corporations, whose performance is both very important for Thailand's overall economy and for the firm's continued presence in Thailand. The study was conducted using a survey methodology. A convenience sample of employees of multinational corporations (n = 423) completed a survey on employee engagement and individual performance outcomes. The data were analyzed using linear regression analysis. The results showed that there was a significant, positive relationship between employee engagement and all four performance outcomes that were targeted. The strongest effect was observed for achievement (β = 0.899), followed by growth (β = 0.887), contribution (β = 0.872), and customer satisfaction (β = .867). These findings indicate that employee engagement is a significant and strong factor that determines the individual performance of employees of multinational corporations. This implies that companies do need to consider how to promote employee engagement. There were some limitations, especially social response bias and the self-reported nature of performance, that limit these findings.

• Journal of muscle and joint health
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• v.25 no.3
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• pp.205-217
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• 2018

Purpose: The purpose of this review was to analyze the characteristics and effectiveness of online-based intervention for infertile women. Methods: We established the PICO (Participant-Intervention-Comparison-Outcome) strategy and conducted a systematic review of 7 literatures retrieved from 3 electronic databases of Ovid-Medline, Ovid-Embase, and the Cochrane Library. Two investigators independently extracted the data and assessed the quality of included studies using Cochrane risk of bias. Results: The pregnancy outcome showed that higher total risk scores (TRS) about lifestyle behavior was significantly associated with lower chance of pregnancy (aHR 0.79, 95% CI 0.72~0.85). Stress was significantly decreased in experimental groups receiving online-based interventions (p<.05). Depression score was significantly lower in groups receiving additional interventions besides on-line interventions than those who used online-based intervention only. The other outcomes, including anxiety, self-efficacy, helpfulness of intervention, perceived social support, and knowledge scores were not significantly different within and between groups in overall. Characteristics of the interventions were heterogeneous. Conclusion: There is evidence that online-based intervention in infertile women enhances the pregnancy and reduces stress levels.