• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.7
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• pp.68-73
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• 2009

This paper describes design and implementation of a spread spectrum clock generator (SSCG) for the DisplayPort. The proposed architecture generates the spread spectrum clock using a sigma-delta fractional-N PLL. The SSCG uses a digital End order MASH 1-1 sigma-delta modulator and a 9bit Up/Dn counter. By using MASH 1-1 sigma-delta modulator, complexity of circuit and chip area can be reduced. The advantage of sigma-delta modulator is the better control over modulation frequency and spread ratio. The SSCG generates dual clock rates which are 270MHz and 162MHz with 0.25% down-spreading and triangular waveform frequency modulation of 33kHz. The peak power reduction is 11.1dBm at 270MHz. The circuit has been designed and fabricated using in 0.18$\mu$m CMOS technology. The chip occupies 0.620mm$\times$0.780mm. The measurement results show that the fabricated chip satisfies the DispalyPort standard.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.49-57
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• 2008

The purpose of this study was to determine the effects of 12-week elastic resistance exercise for the elderly on the magnitude of frequency and variability of ground reaction force signals. To this aim, total 12 elderly women aged in their 70 were participated in this study and asked to do a 12-week elastic resistance exercise program. FFT(fast Fourier Transform) was used to analyze the frequency domain analysis of the ground reaction forces's signals and an accumulative PSD (power spectrum density) normalized by support phase of walking was calculated to reconstruct the certain signals. To estimate the gait stability between the before and after exercise, values of variability were determined in a coefficient of variance. The magnitude of frequency and variability analysis for media-lateral signal revealed significantly less after exercise (p<.05). In contrast, variability of this signal's frequency that have used to evaluate the local stability during walking exhibited significantly greater after exercise(p<.05). In summary, magnitude frequency and variability of media-lateral ground reaction force's signal were significantly changed after a 12-week elastic resistance exercise.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.9
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• pp.624-633
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• 2001

Influence of the grating half-period fluctuation on the normalized coupling coefficient has been studied by an effective index transfer matrix method in quarter wavelength shifted(QWS) DFB lasers. The laser facets are assumed to be perfectly antireflection coated, and the period fluctuation is modeled by two correlated Gaussian random variables. In the presence of the random fluctuation in the grating period, effective normalized coupling coefficient is reduced because the in-phase feedback strength Is weakened. We have shown that the normalized coupling coefficient determined from the side mode spacing is less than the effective coupling coefficient, and the normalized coupling coefficient determined from the mode spacing or spontaneous emission spectrum does not properly represent the feedback strength of the grating.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.5
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• pp.9-15
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• 2000

The 3 ${\mu}{\textrm}{m}$-thick PVDF (polyvinylidene fluoride) thin film have been prepared using physical vapor deposition with electric field, and its FT-IR spectrum, dielectric property and electric conduction phenomenon have been investigated. Since the characteristic peaks are detected at 509.45 ［$cm^{-1}$ /］ and 1273.6 ［$cm^{-1}$ /］in the FT-IR spectrum, we are confirmed that the $\beta$ -phase is dominant in the PVDF thin film. In the results of dielectric properties, the PVDF thin film shows anomalous dispersion, i.e. gradual decrease of dielectric constant with increase of frequency, and also that the dielectric absorption point changes from 200 Hz to 7000 Hz with increasing temperature of thin film, which is consistent with the Debye's theory. The activation energy ( $\Delta$H) obtained from temperature dependence of dielectric loss is 21.64 ㎉/mole. We confirm that the electric conduction mechanism of PVDF thin film is dominated by ionic conduction by investigating the dependence of the leakage current of the thin film on the temperature and the electric field.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.925-928
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• 2014

Background: Gestational trophoblastic neoplasia (GTN) is a spectrum of disease with abnormal trophoblastic proliferation. Treatment is based on FIGO stage and WHO risk factor scores. Patients whose score is 12 or more are considered as at extremely high risk with a high likelihood of resistance to first line treatment. Optimal therapy is therefore controversial. Objective: This study was conducted in order to summarize the regimen used for extremely high risk or resistant GTN patients in our institution the in past 10 years. Materials and Methods: All the charts of GTN patients classified as extremely high risk, recurrent or resistant during 1 January 2002 to 31 December 2011 were reviewed. Criteria for diagnosis of GTN were also assessed to confirm the diagnosis. FIGO stage and WHO risk prognostic score were also re-calculated to ensure the accuracy of the information. Patient characteristics were reviewed in the aspects of age, weight, height, BMI, presenting symptoms, metastatic area, lesions, FIGO stage, WHO risk factor score, serum hCG level, treatment regimen, adjuvant treatments, side effects and response to treatment, including disease free survival. Results: Eight patients meeting the criteria of extremely high risk or resistant GTN were included in this review. Mean age was 33.6 years (SD=13.5, range 17-53). Of the total, 3 were stage III (37.5%) and 5 were stage IV (62.5%). Mean duration from previous pregnancies to GTN was 17.6 months (SD 9.9). Mean serum hCG level was 864,589 mIU/ml (SD 98,151). Presenting symptoms of the patients were various such as hemoptysis, abdominal pain, headache, heavy vaginal bleeding and stroke. The most commonly used first line chemotherapeutic regimen in our institution was the VAC regimen which was given to 4 of 8 patients in this study. The most common second line chemotherapy was EMACO. Adjuvant radiation was given to most of the patients who had brain metastasis. Most of the patients have to delay chemotherapy for 1-2 weeks due to grade 2-3 leukopenia and require G-CSF to rescue from neutropenia. Five form 8 patients were still survived. Mean of disease free survival was 20.4 months. Two patients died of the disease, while another one patient died from sepsis of pressure sore wound. None of surviving patients developed recurrence of disease after complete treatment. Conclusions: In extremely high risk GTN patients, main treatment is multi-agent chemotherapy. In our institution, we usually use VAC as a first line treatment of high risk GTN, but since resistance is quite common, this may not suitable for extremely high risk GTN patients. The most commonly used second line multi-agent chemotherapy in our institution is EMA-CO. Adjuvant brain radiation was administered to most of the patients with brain metastasis in our institution. The survival rate is comparable to previous reviews. Our treatment demonstrated differences from other institutions but the survival is comparable. The limitation of this review is the number of cases is small due to rarity of the disease. Further trials or multicenter analyses may be considered.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.10
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• pp.43-47
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• 2002

A simple optical signal to noise ratio monitoring method using fiber Bragg grating is proposed for monitoring performance of OADM. OSNR of each channel is determined by monitoring the optical power transmitted and reflected from fiber Bragg gratings, simultaneously. We have obtained OSNR with accuracy better than 0.8㏈ compared with OSA of 0.1nm optical resolution in the wide input power range between -6 ㏈m and -23㏈m per channel.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.95-101
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• 2008

We have used diversely the multilayer ceramic oscillator of the SMD(Surface Mounted Device) package technology that connects the crystal with the chip package. Such an oscillator occurs a stray inductance and a parasitic capacitance by the length and inner pattern. And it has been happened an amplitude attenuation and signal loss due to the reflection of power source and noise component. So we don't evaluate the precise performance of the oscillator for these factors. In this paper we have developed the Jig system to evaluate the performance of the oscillator. Through this system, we will expect an advanced performance of the oscillator and redesign an oscillator of the low jitter characteristics and low phase noise.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.29-34
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• 2008

The propagation characteristics of novel grating-assisted multimode interference (GA-MMI) coupler are explicitly and theoretically investigated by using longitudinal modal transmission-line theory (L-MTLT). The coupling efficiency of GA-MMI coupler is evaluated along the variation of grating thickness and duty cycle, and the spectrum is analyzed numerically. The numerical results reveal that the coupling length and the efficiency of $2{\times}2$ GA-MMI coupler along the variation of grating structure have low tolerance and the bandwidth varies dramatically along the output states.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.1-6
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• 2004

In this study, heat and discharge treatments are arbitrary simulated for finding out the initiations and processes of surface degradation on the surface of polymer for using as a PCB substrate. Thermal-treatment changed the surface to the hydrophobic one with the increase of contact angle and surface potential decay, respectively. The XPS spectrum showed that the increased hydrophobicity in thermal treatment was originated from the continuous decrease of side-chains caused by secessions of oxygen groups and the increase of unsaturated double bond in carbon chains. Also, thermal-treatment caused the discoloration on the point of treated surface. These phenomena were attributed to the generation of ether group. In the chemical change by discharge treatment, a lot of side-chains occurred on the treated surface, and so the hydrophilicity increased as time elapsed.

• Journal of the Korean earth science society
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• v.38 no.7
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• pp.535-545
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• 2017

Maritime accidents around the Korean Peninsula are increasing, and the ship detection research using remote sensing data is consequently becoming increasingly important. This study presented a new ship detection algorithm using hyperspectral images that provide the spectral information of several hundred channels in the ship detection field, which depends on high resolution optical imagery. We applied a spectral matching algorithm between the reflection spectrum of the ship deck obtained from two field observations and the ship and seawater spectrum of the hyperspectral sensor of an airborne visible/infrared imaging spectrometer. A total of five detection algorithms were used, namely spectral distance similarity (SDS), spectral correlation similarity (SCS), spectral similarity value (SSV), spectral angle mapper (SAM), and spectral information divergence (SID). SDS showed an error in the detection of seawater inside the ship, and SAM showed a clear classification result with a difference between ship and seawater of approximately 1.8 times. Additionally, the present study classified the vessels included in hyperspectral images by presenting the adaptive thresholds of each technique. As a result, SAM and SID showed superior ship detection abilities compared to those of other detection algorithms.