• 한국융합학회논문지
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• 제10권5호
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• pp.27-34
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• 2019

본 논문에서는 문자 영역의 패턴을 분석하여 배경 영역을 제거하는 방법을 제안하였다. 명암이 일정한 영역을 구분하는 MSER(Maximally Stable External Regions)방법의 문자 검출에서는 배경 영역이 포함되어 검출되었다. 이러한 문제점을 해결하기 위해 자연 이미지에서 MSER 방법을 사용하여 명암 값이 차이가 나는 영역과 차이가 나지 않는 영역 즉 문자 영역과 배경 영역을 구해 변화율을 계산하여 배경을 제거하였다. 그러나 배경이 제거된 이미지에서 일부 제거되지 않는 배경 영역이 생겨 LBP(Local Binary Patterns)방법을 사용하여 이미지에서 균일한 값을 갖는 영역을 문자 영역이라고 판단하고 문자를 검출하였다. 실험 데이터는 배경이 단순한 이미지, 문자가 정면으로 구성된 이미지, 문자가 기울어진 이미지 등의 다양한 자연 이미지를 실험하였다. 제안하는 방법을 기존의 MSER, MSER+LBP 방법의 문자 검출 방법과 비교하였을 때 약 1.73%로 높은 검출률을 보였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1334-1335
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• 2008

Although many studies have been carried out about binary gas mixtures with $SF_6$, few studies were presented about breakdown characteristics of $SF_6/CF_4$ mixtures. At present study the breakdown characteristics of $SF_6/CF_4$ mixtures in uniform and nonuniform field was performed. The experiments were carried out under AC voltages. The sphere-sphere electrode whose gap distance was 1 mm was used and the point-plane electrode whose gap distance was 3 mm was used in a test chamber. $SF_6/CF_4$ mixture contained 20% $SF_6$ and 80% $CF_4$ and the experimental gas pressure ranged from 0.1 to 0.5 MPa. The results show that addition of $SF_6/CF_4$ mixtures increase AC breakdown voltages. In uniform field the breakdown voltages of gas were linearly increased according to the pressure. However in nonuniform field the breakdown voltages of gas were increased nonlinearly.

• 성인간호학회지
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• 제26권2호
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• pp.159-170
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• 2014

Purpose: This research investigated the degree and predictors of hot flashes and hypogonadism symptoms in patients with prostate cancer receiving hormone replacement therapy. Methods: The subjects were 111 patients with prostate cancer receiving hormone replacement therapy in two university hospitals located in D city. The measurement tools included Hot Flash Diary and AMS (Aging Male's Symptoms rating scales). The data were analyzed using t-test, ANOVA, and binary logistic regression analysis. Results: The percentage of patients who experienced hot flashes among the participants was 14.4%. The predictors for hot flashes were eating irregularly, having coffee frequently and the types of hormone. The average score of hypogonadism symptom was 2.16 out of five-point scale and the highest score of hypogonadism symptom was the sexual symptoms (2.77 out of five-point scale). The predictors for hypogonadism symptom were eating habits and years of having the illness. Conclusion: These findings provide the information that irregularly eating habit was an important factor in hot flashes and hypogonadism symptoms of the participants. Therefore the development of a nutritional education encouraging regular meals is necessary for the given population.

• 정보관리학회지
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• 제23권1호
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• pp.243-259
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• 2006

본 연구에서는 대학 도서관들이 이용자들에게 제공하는 여러 가지 기능들을 조사하고 그 가치를 측정하였다. 이용자들의 판단을 중시하는 연구의 수행을 위해 구체적인 대학 도서관의 이용요인이나 기능이 될 수 있는 상황이나 조건들은 이용자들이 직접 설정하고 그 중요도 평가를 설문조사방법으로 수집하였다. 수집된 자료의 분석은 크게 세 단계로 나누어 시행하였다. 첫째, 측정변수들의 관련성 및 독특성, 그리고 통계적 중요도에 따른 요인을 영역별로 나누기 위해 요인분석을 실시하였다. 둘째, 연구모형을 도출하기 위해 이분 로지스틱 회귀분석(binary logistic regression)을 실시하여 판별력 향상을 검정하였다. 세 번째 분석에서는 연구모형의 독립변수들에 대해 집단간 평균차이 분석을 실시하여 집단별 변수값 등 부가적인 설명을 하였다. 분석결과, 이용자들이 대학 도서관을 활용하는 목적 뿐만 아니라 이용자들에게 끼치는 지식이나 정보 그리고 도서관 시설들을 설명하는 데에는 도서요인, 경쟁 및 효율요인, 그리고 지불(무료)요인 등이 있음이 밝혀졌다. 또한 본 연구에서는 전자도서관 기능과 지불요인과의 상관성도 통계적으로 유의하게 나타났다.

• 한국통신학회논문지
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• 제27권3C호
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• pp.256-262
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• 2002

본 논문에서는 sign estimation technique (3)을 기초로 한 radix-4 모듈라 곱셈 알고리즘을 제안한다. Sign estimation technique은 carry와 sum의 형태로 표현되는 수에서 부호를 알아내는 것이다. 이 방법은 5비트 carry look-ahead adder로 구현이 가능하다. RSA와 같은 암호화 시스템에서는 모듈라 곱셈이 하드웨어의 성능을 좌우한다. 제안한 알고리즘은 modulus가 n 비트인 경우, 모듈라 곱셈 수행시 일반적인 알고리즘의 약 반 클럭 (n/2+3) 사이클만 필요하다. 그래서 매우 큰수의 modulus 사용하는 RSA 암호시스템에서 모듈라 멱승 연산에 매우 효율적이다. 또한 모듈라 곱셈의 하드웨어 성능을 향상하기 위해, CSA (Carry Save Adder)의 맨 마지막 출력에 사용되는 CPA (Carry Propagation Adder) 대신 고속 덧셈기(7)를 사용하였다. 모듈라 멱승 계산이 n 클럭이 소요되는 RL binary 방법을 적용하여 1024 비트 데이터를 RSA 암호화하는데 n(n/2+3) 클럭 사이클만 소요된다.

• Journal of Electrochemical Science and Technology
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• 제12권1호
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• pp.58-66
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• 2021

Spiral-wound woven wire meshes packed bed rotating cylinder electrode was used for the simultaneous removal of cadmium (Cd) and copper (Cu) from a binary solution. The effects of weight percent of each metal on the removal and current efficiencies were studied at an operating current of 345A, while the effect of current on the removal efficiency of both metals was investigated at three levels of current (240, 345.and 400 mA). The experiments were carried out at constant rotation speed 800 rpm, pH = 3, and a total concentration of metals (500 ppm). The results showed that the removal efficiency of copper increased from 89% to 99.4% as its weight percent increased from 20% to100%. In a similar fashion, the removal efficiency of cadmium increased from 81% to 97% as its weight percent increased from 20% to100%. The results confirmed that the removal efficiency of any metals declined in the presence of the other. Increasing of current resulted in increasing the removal efficiency of both metals at different weight percents. The results confirmed that current efficiencies for removing of copper and cadmium simultaneously decline with increasing of electrolysis time and weight percent of cadmium or with decreasing the weight percent of copper. Current efficiency was higher at the initial stage of electrolysis for all weight percents of metals. The results showed that the decay of copper concentration was exponential at all weight percents of copper, confirming that the electrodeposition of copper is under mass transfer control in the presence of cadmium. While the decay of cadmium concentration was linear at lower weight percent of cadmium then changed to an exponential behavior at high weight percent of cadmium in the presence of copper.

• Communications for Statistical Applications and Methods
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• 제29권5호
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• pp.499-512
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• 2022

Intervention measures have been implemented worldwide to reduce the spread of the COVID-19 outbreak. The COVID-19 outbreak has occured in several waves of infection, so this paper is divided into three groups, namely those countries who have passed the pandemic period, those countries who are still experiencing a single-wave pandemic, and those countries who are experiencing a multi-wave pandemic. The purpose of this study is to develop a multi-wave Richards model with several changepoint detection methods so as to obtain more accurate prediction results, especially for the multi-wave case. We investigated epidemiological trends in different countries from January 2020 to October 2021 to determine the temporal changes during the epidemic with respect to the intervention strategy used. In this article, we adjust the daily cumulative epidemiological data for COVID-19 using the logistic growth model and the multi-wave Richards curve development model. The changepoint detection methods used include the interpolation method, the Pruned Exact Linear Time (PELT) method, and the Binary Segmentation (BS) method. The results of the analysis using 9 countries show that the Richards model development can be used to analyze multi-wave data using changepoint detection so that the initial data used for prediction on the last wave can be determined precisely. The changepoint used is the coincident changepoint generated by the PELT and BS methods. The interpolation method is only used to find out how many pandemic waves have occurred in given a country. Several waves have been identified and can better describe the data. Our results can find the peak of the pandemic and when it will end in each country, both for a single-wave pandemic and a multi-wave pandemic.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1520-1523
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• 1997

A rigorous dynamic simulation was performed in binary gas mixture H$_{2}$/CO (70:30 vol.%) to determinate start-up operating conditions of PSA(Pressure Swing Adsorption) processes. The rigorous dynamic model for the PSA process contains an Ergun equation for expressing the pressure drop in a bed, and valve equations to compute the boundary pressure change of the bed. As the result of the continuous dynamic simulation of 100 operating cyles in various initial conditions, the unsteady-state appeared in the early period and the cyclic steady-state came out about 20th cycle in feed condition and vaccum condition, and 30th cycle in pure H$_{2}$ condition. As time goes by valve equations made change the pressure at each end of the bed in ressurization, countercurrunt-depressurization and pressure equalization steps. The H$_{2}$ purity and the recovery is 99.99% and 86.73% respectively, which is slightly higher than the experimental data. Main contributiion of this study includes supplying fundamental technologies of handling combined variables PSA processes by developing rigorous models.

• Interaction and multiscale mechanics
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• 제6권1호
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• pp.15-29
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• 2013

Phononic system composed of periodical elastic structures exhibit band gap phenomenon, and all elastic wave cannot propagate within the band gap. In this article, we consider one-dimensional binary materials which are periodically arranged as a 20-layered medium instead of infinite layered system for phononic system. The layered medium with finite dimension is subjected to a uniformly distributed sinusoidal loading at the upper surface, and the bottom surface is assumed to be traction free. The transient wave propagation in the 20-layered medium is analyzed by Laplace transform technique. The analytical solutions are presented in the transform domain and the numerical Laplace inversion (Durbin's formula) is performed to obtain the transient response in time domain. The numerical results show that when a sinusoidal loading with a specific frequency within band gap is applied, stress response will be significantly decayed if the receiver is away from the source. However, when a sinusoidal force with frequency is out of band gap, the attenuation of the stress response is not obvious as that in the band gap.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.201-205
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• 1989

In this study, the vertical type LPE system has been developed by fully hand-made. The temperature fluctuation and minimum cooling rate of this LPE system are within $\pm$0.05$^{\circ}C$ and 0.15$^{\circ}C$/min, respectively. It is considered that these properties are enough to grow III-V semiconductor compounds single crystals by liquid phase epitaxy method. Futhermore in this study. 1.3${\mu}{\textrm}{m}$ GaInAsP/InP single crystal growing has been carried out by this system. It has been obtained that the growing rate was about 0.72${\mu}{\textrm}{m}$/min for InP binary layer and 0.36${\mu}{\textrm}{m}$/min for GaInAsP quarternary layer under 0.6$^{\circ}C$/min cooling rate condition.