• 대한피부과학회지
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• 제56권9호
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• pp.552-555
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• 2018

Vitiligo is a commonly acquired cutaneous depigmentation disorder that affects 0.5~1% of the population worldwide. While phototherapy is the primary treatment for vitiligo, surgical methods can be used for treating patients who are refractory to conventional treatments. Herein, we present the case of a 14-year-old Korean girl who developed vitiligo after hematopoietic stem cell transplantation for the treatment of acute lymphoblastic leukemia. She had multiple depigmented patches on her lower legs that did not respond to narrow-band ultraviolet B phototherapy for 7 months. The depigmented patches were successfully treated by transplantation of non-cultured epidermal cell suspension from the epidermal roof of the suction blister in the right inner thigh. No adverse event, such as secondary infection or scarring in both the donor and recipient sites, was noted. We recommended that non-cultured epidermal cell suspension transplantation using the suction blister method would be a safe and effective option for the treatment of refractory vitiligo.

• Wind and Structures
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• 제14권6호
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• pp.517-536
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• 2011

The assessment of wind-induced motion plays an important role in the development and design of the majority of today's structures that push the limits of engineering knowledge. A vital part of the design is the prediction of wind-induced tall building motion and the assessment of its effects on occupant comfort. Little of the research that has led to the development of the various international standards for occupant comfort criteria have considered the effects of the low-frequency motion on task performance and interference with building occupants' daily activities. It has only recently become more widely recognized that it is no longer reasonable to assume that the level of motion that a tall building undergoes in a windstorm will fall below an occupants' level of perception and little is known about how this motion perception could also impact on task performance. Experimental research was conducted to evaluate the performance of individuals engaged in a manual tracking task while subjected to low level vibration in the frequency range of 0.125 Hz-0.50 Hz. The investigations were carried out under narrow-band random vibration with accelerations ranging from 2 milli-g to 30 milli-g (where 1 milli-g = 0.0098 $m/s^2$) and included a control condition. The frequencies and accelerations simulated are representative of the level of motion expected to occur in a tall building (heights in the range of 100 m -350 m) once every few months to once every few years. Performance of the test subjects with and without vibration was determined for 15 separate test conditions and evaluated in terms of time taken to complete a task and accuracy per trial. Overall, the performance under the vibration conditions did not vary significantly from that of the control condition, nor was there a statistically significant degradation or improvement trend in performance ability as a function of increasing frequency or acceleration.

• Journal of the Optical Society of Korea
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• 제18권3호
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• pp.261-273
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• 2014

In this paper, metal insulator metal (MIM) plasmonic slot cavity narrow band-pass filters (NBPFs) are studied. The metal and dielectric of the structures are silver (Ag) and air, respectively. To improve the quality factor and attenuation range, two novel NBPFs based on tapered structures and double cavity systems are proposed and numerically analyzed by using the two-dimensional (2-D) finite difference time domain (FDTD) method. The impact of different parameters on the transmission spectrum is scrutinized. We have shown that increasing the cavities' lengths increases the resonance wavelength in a linear relationship, and also increases the quality factor, and simultaneously the attenuation of the wave transmitted through the cavities. Furthermore, increasing the slope of tapers of the input and output waveguides decreases attenuation of the wave transmitted through the waveguide, but simultaneously decreases the quality factor, hence there should be a trade-off between loss and quality factor. However, the idea of adding tapers to the waveguides' discontinuities of the simple structure helps us to improve the device total performance, such as quality factor for the single cavity and attenuation range for the double cavity. According to the proposed NBPFs, two, three, and four-port power splitters functioning at 1320 nm and novel ultra-compact two-wavelength and triple-wavelength demultiplexers in the range of 1300-1550 nm are proposed and the impacts of different parameters on their performances are numerically investigated. The idea of using tapered waveguides at the structure discontinuities facilitates the design of ultra-compact demultiplexers and splitters.

• 말소리와 음성과학
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• 제13권3호
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• pp.31-37
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• 2021

The fundamental frequency, or f0, is an important acoustic measure in the prosody of human speech. The current study examined the f0 distribution of a corpus of spontaneous speech in order to provide normative data for Korean speakers. The corpus consists of 40 speakers talking freely about their daily activities and their personal views. Praat scripts were created to collect f0 values, and a majority of obvious errors were corrected manually by watching and listening to the f0 contour on a narrow-band spectrogram. Statistical analyses of the f0 distribution were conducted using R. The results showed that the f0 values of all the Korean speakers were right-skewed, with a pointy distribution. The speakers produced spontaneous speech within a frequency range of 274 Hz (from 65 Hz to 339 Hz), excluding statistical outliers. The mode of the total f0 data was 102 Hz. The female f0 range, with a bimodal distribution, appeared wider than that of the male group. Regression analyses based on age and f0 values yielded negligible R-squared values. As the mode of an individual speaker could be predicted from the median, either the median or mode could serve as a good reference for the individual f0 range. Finally, an analysis of the continuous f0 points of intonational phrases revealed that the initial and final segments of the phrases yielded several f0 measurement errors. From these results, we conclude that an examination of a spontaneous speech corpus can provide linguists with useful measures to generalize acoustic properties of f0 variability in a language by an individual or groups. Further studies would be desirable of the use of statistical measures to secure reliable f0 values of individual speakers.

• 한국정보전자통신기술학회논문지
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• 제11권6호
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• pp.651-657
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• 2018

스퍼의 크기를 줄이기 위해 델타-시그마 변조기와 스퍼감소회로가 도입된 위상고정루프(PLL)를 제안하였다. 델타-시그마 변조기는 스퍼 잡음을 높은 주파수 대역으로 이동시켜 루프필터가 잡음 제거를 쉽게 할 수 있도록 해준다. 이는 위상고정루프의 대역폭을 적절히 조절하면 스퍼 크기를 크게 감소시킬 수 있다. 스퍼감소회로는 한주기당 발생하는 루프필터 전압변화를 작게 하여 스퍼 크기가 감소되도록 한다. 제안한 스퍼감소회로는 위상고정루프의 크기에 거의 영향이 없을 정도로 간단하게 설계하였다. 이 두 가지 방법을 사용한 제안된 위상고정루프는 $0.18{\mu}m$ CMOS 공정에서 1.8V의 공급전압으로 설계되었으며, 시뮬레이션을 통해 제안된 위상고정루프의 스퍼 크기가 거의 20dB 감소된 것을 확인하였다. 스퍼의 크기가 크게 감소된 위상고정루프는 대역폭이 좁은 통신시스템에 크게 활용될 수 있다.

• 패션비즈니스
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• 제22권5호
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• pp.96-112
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• 2018

This study developed the pants pattern, that improved appearance and gesture functions in clothes to resolve inconveniences in case of activities with being adequate in fitness of slim-fit pants for obese adolescents. The slim-fit pants pattern was developed through the fitting test after designing and making the pattern of the experimental clothing A(c/pu; 99/1%) with the primary commercial clothing as basic prototype, through the fitting test and implementation of the experimental clothing, modified and supplemented secondarily, and through the fitting test of the second experimental clothing, modified and supplemented tertiary. In terms of findings, first, as a result of analyzing the commercial slim-fit pants, it is interpreted to have projected an optical illusion, that appears to be slim due to being narrow in width of the front panel when observed from the front of the pants. Second, in the fitting test of the first experimental clothing, the prototype of commercial clothing was understood to have improved butt, crotch, waist and femoral regions. Third, pattern design of the second experimental clothing was allowed to decline abdominal pressure, in case of the sitting position, by making the crotch line in the front panel short and by handling it with a yoke belt, and was processed a difference between waist and hip circumference in the back panel, with a rubber band in the whole waist part. Fourth, in the gesture function test of the third experimental clothing, high evaluation was received in every item excluding the knee region.

• 한국재료학회지
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• 제29권9호
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• pp.553-558
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• 2019

$Cu_2ZnSn(S,Se)_4(CZTSSe)$ thin film solar cells areone of the most promising candidates for photovoltaic devices due to their earth-abundant composition, high absorption coefficient and appropriate band gap. The sputtering process is the main challenge to achieving high efficiency of CZTSSe solar cells for industrialization. In this study, we fabricated CZTSSe absorbers on Mo coated soda lime glass using different pressures during the annealing process. As an environmental strategy, the annealing process is performed with S and Se powder, without any toxic $H_2Se$ and/or $H_2S$ gases. Because CZTSSe thin films have a very narrow stable phase region, it is important to control the condition of the annealing process to achieve high efficiency of the solar cell. To identify the effect of process pressure during the sulfo-selenization, we experiment with varying initial pressure from 600 Torr to 800 Torr. We fabricate a CZTSSe thin film solar cell with 8.24 % efficiency, with 435 mV for open circuit voltage($V_{OC}$) and $36.98mA/cm^2$ for short circuit current density($J_{SC}$), under a highest process pressure of 800 Torr.

• 전력전자학회논문지
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• 제26권3호
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• pp.214-221
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• 2021

SiC MOSFETs require a faster and more reliable short-circuit protection circuit than conventional methods due to narrow short-circuit withstand times. Therefore, this research proposes a short-circuit protection circuit using a current-sensing circuit based on Rogowski coil. The method of designing the current-sensing circuit, which is a component of the proposed circuit, is presented first. The integrator and input/output filter that compose the current-sensing circuit are designed to have a wide bandwidth for accurately measuring short-circuit currents with high di/dt. The precision of the designed sensing circuit is verified on a double pulse test (DPT). In addition, the sensing accuracy according to the bandwidth of the filters and the number of turns of the Rogowski coil is analyzed. Next, the entire short-circuit protection circuit with the current-sensing circuit is designed in consideration of the fast short-circuit shutdown time. To verify the performance of this circuit, a short-circuit test is conducted for two cases of short-circuit conditions that can occur in the half-bridge structure. Finally, the short-circuit shutdown time is measured to confirm the suitability of the proposed protection circuit for the SiC MOSFET short-circuit protection.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권11호
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• pp.3544-3564
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• 2022

With the development of the NB-IoT (Narrow band Internet of Things) and smart cities, coupled with the emergence of smart smoke sensors, new requirements and issues have been introduced to study on the deployment of sensors in large spaces. Previous research mainly focuses on the optimization of wireless sensors in some monitoring environments, including three-dimensional terrain or underwater space. There are relatively few studies on the optimization deployment problem of smart smoke sensors, and leaving large spaces with obstacles such as libraries out of consideration. This paper mainly studies the deployment issue of smart smoke sensors in large spaces by considering the fire probability of fire areas and the obstacles in a monitoring area. To cope with the problems of coverage blind areas and coverage redundancy when sensors are deployed randomly in large spaces, we proposed an optimized deployment strategy of smart smoke sensors based on the PSO (Particle Swarm Optimization) algorithm. The deployment problem is transformed into a multi-objective optimization problem with many constraints of fire probability and barriers, while minimizing the deployment cost and maximizing the coverage accuracy. In this regard, we describe the structure model in large space and a coverage model firstly, then a mathematical model containing two objective functions is established. Finally, a deployment strategy based on PSO algorithm is designed, and the performance of the deployment strategy is verified by a number of simulation experiments. The obtained experimental and numerical results demonstrates that our proposed strategy can obtain better performance than uniform deployment strategies in terms of all the objectives concerned, further demonstrates the effectiveness of our strategy. Additionally, the strategy we proposed also provides theoretical guidance and a practical basis for fire emergency management and other departments to better deploy smart smoke sensors in a large space.

• 한국음향학회지
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• 제42권4호
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• pp.345-356
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• 2023

수동소나의 표적신호는 수초 내 세기의 변화를 갖는 협대역 고조파 특성과 로이드 거울 효과에 의한 장시간 주파수 변이 특성을 나타낸다. 본 논문에서는 지역 및 전역적 시계열 특징을 학습하는 게이트 순환 유닛 기반의 신호분류 알고리즘을 제안한다. 제안하는 알고리즘은 게이트 순환 유닛을 이용한 다층 네트워크를 구성하고 확장된 연결을 통해 지역 및 전역적 시계열 특징들을 추출한다. 이후 어텐션 메커니즘을 학습하여 시계열 특징들을 가중하고 수동소나 신호를 분류한다. 공개된 수중 음향 데이터를 이용한 실험에서 제안된 네트워크는 96.50 %의 우수한 분류 정확도를 보였다. 이러한 결과는 기존의 잔차 연결된 게이트 순환 유닛 네트워크과 비교하여 4.17 % 높은 분류 정확도를 갖는다.