• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2075-2076
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• 2011

The stator winding faults diagnosis technique based on MCSA is as follows. Firstly, collecting the 3 phase motor currents, that signal is transformed by (d-q transform, $i_d$, $i_q$). Park's vector pattern, the circle that is down by d-q transformed currents($i_d$, $i_q$). The circle is widely used for stator winding faults detection. The current distortion ratio(DR), defined by the ratio of max-axis and min-axis of ellipse of Park's vector's pattern. In this study, distortion ratio of Park's vector pattern is suggested for Auto diagnosis of stator winding short fault and usefulness of distortion ratio is verified through simulation using LabVIEW program.

• 산업경영시스템학회지
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• 제9권14호
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• pp.49-58
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• 1986

Those facts I have studied on the theoretical characteristics of stock price earning ratio related with firm evaluation are as followings. First, I have investigated stock valuation analysis under certainty in view of Miller's, Modigliani's and Linter's theories in Chapter Ⅱ, and it is found that stock valuation under uncertainty to which the basic model of MM theory and the concept of capitalization ratio are applied is the same output, as in the case under certainty. And I have examined the stock valuation of growth corporations in which net investment, total capitals and operating profits are expected. Second, I have reexamined the fact that stock price profits are the erotical indices of firm valuation and the firm valuation on the basis of stock price earning ratio in Chapter III. As a whole, I have surveyed the stock price earning ratio theory of the growth stocks and there have been found some problems as such scholars as Malkiel and others have suggested focusing on the stock price structure of growth stocks. To conclude, there must be incessant efforts for the study of security analysis to make it develop ideally.

• 대한기계학회논문집B
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• 제23권11호
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• pp.1390-1398
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• 1999

A numerical analysis for ROT sparger of PWR(Pressurized Water Reactor) is carried out. Computation is performed to investigate the flow characteristics as the change of design factor. As the result of this study, RDT sparger's flow resistance coefficient is K=3.53 at the present design condition if engineering mar&in is considered with 20%, and flow ratio into branch pipe is $Q_s/Q_i=0.41$. Velocity distribution at exit is not uniform because of separation in branch pipe. In the change of inlet flow rate and section area ratio of branch pipe for main pipe, flow resistance coefficient is increased as $Q_s/Q_i$ decreasing, but in the change of branch angle and outlet nozzle diameter of main pipe, flow resistance coefficient is decreased as $Q_s/Q_i$ decreasing. As the change rate of $Q_s/Q_i$ is the larger, the change rate of flow resistance coefficient is the larger. The change rate of pressure loss is the largest change as section area ratio changing. The optimal design condition of sparger is estimated as the outlet nozzle diameter ratio of main pipe is $D_s/D_i=0.333$, the section area ratio is $A_s/A_i=0.2$ and the branch angle is ${\alpha}=55^{\circ}$.

• Journal of Gastric Cancer
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• 제9권3호
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• pp.78-87
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• 2009

위암 발생률이 높은 우리나라에서는 위암이 발생할 가능성이 높은 고위험군에서 위암 발생 여부를 알 수 있는 생물학적 인자(biological marker)의 개발이 매우 중요한데 가장 많이 연구되는 인자로 혈청 펩시노겐(Pepsinogen)이 있다. 이에 소화기질환을 가지고 있는 환자군과 건강검진센터 수진자를 대상으로 한두 가지 연구에서 혈청 펩시노겐 검사에 영향을 주는 인자를 알아보고 위축성 위염이나 위암 진단에 있어 혈청 펩시노겐 검사의 역할을 알아보았다. 혈청 펩시노겐 검사에 영향을 주는 인자로는 H. pylori 감염이 가장 컸고, 다음으로 성별, 연령이 있었다. 이를 고려한 결과 한국인에서의 내시경적 위축성 위염 진단에 있어서 PG I/II ratio 기준은 H. pylori 감염 여부에 따라 달랐는데 H. pylori 감염이 없는 경우는 PG I/II ratio 6이, H. pylori 감염이 있는 경우는 국제적 기준인 PG I/II ratio 3이 예민도와 민감도에서 우수했다. 또한 한국인에서의 위암이나 위축성 위염 진단에 있어 PG I이나 PG II는 별로 유용하지 않은 반면 PG I/II ratio는 비교적 유용함을 알 수 있었고, 특히 H. pylori 감염이 있는 경우 PG I/II ratio $\leq3$ 이하가 위암 발생위험도 예측에 도움이 되었다. 결과적으로 혈청 펩시노겐을 위암이나 위축성 위염 진단 biomarker로 사용할 때는 기존의 국제적인 기준도 중요하지만 각 나라의 현실에 맞는 기준치 적용을 위해 validation study를 시행하고 사용하는 것이 바람직한 것으로 보인다.

• 대한한의진단학회지
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• 제9권2호
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• pp.123-144
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• 2005

Objectives: Pulse-Respiration Ratio has been used for estimating subject's Han-Yeol [寒熱] status since it mentioned in suwen [素問]. In practicing Pulse-Respiration Ratio over 5 means the status of Yeol [熱], Pulse-Respiration Ratio below 3 means the status of Han [寒]. We performed this study to examine the Optimum Standard for Measuring Pulse-Respiration Ratio on the Basis of Repeatability and Reproducibility. Methods: After subject's 5 minutes rest we measured subject's ECG, respiration pattern, EEG, EMG simultaneously. In this research examiner's number is two, subject's number is four, and the number of repeat is two. We calculated Pulse-Respiration Ratio through dividing Respiration cycle average by Pulse cycle average according to each standard including time section, $EEG(relative-{\alpha}$ density, $relative-{\beta}$ density, ${\alpha}/{\beta}$ and EMG. We analyzed these data through Gage R&R study using MINITAB 13.20 program and considered the results of below 30 %R&R and over 4 Number of Distinct Categories to have a significance. Results: 1. In the applying of time standard, Pulse-Respiration Ratio from section 3, 4, 6, 8 had a significant meaning in the aspect of Repeatability and Reproducibility. 2. In the applying of $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$, EMG(E I) standard, there was no significant results. 3. In the applying of time standard(section 5, 6, 7), $EEG({\alpha}$ I , ${\beta}$ I , ${\alpha}/{\beta})$ and EMG(E I) standard simultaneously, Pulse-Respiration Ratio from ${\alpha}/{\beta}$ in section 6, ${\beta}$ I in section 8 had a significant meaning in the aspect of Repeatability and Reproducibility. Conclusions: We can suggest the Optimum Standard for Measuring Pulse-Respiration Ratio on the basis of Repeatability and Reproducibility as followings; 1. Pulse-Respiration Ratio Measuring time should be at least 15 minutes. 2. Applying of time(section 6, 8) and $EEG({\beta}$ I, ${\alpha}/{\beta})$ standard simultaneously is recommended considering reliability and validity but more study is needed. 3. EMG(E I) may be helpful to detect the segment of physical rest and exclude artifacts but more study is needed.

• Asian-Australasian Journal of Animal Sciences
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• 제27권4호
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• pp.600-607
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• 2014

The aim of this study was to assess the effect of substrate to inoculum ratio (S/I ratio) on the biochemical methane potential (BMP) and anaerobic biodegradability ($D_{deg}$) of different piggery slaughterhouse wastes, such as piggery blood, intestine residue, and digestive tract content. These wastes were sampled from a piggery slaughterhouse located in Kimje, South Korea. Cumulative methane production curves for the wastes were obtained from the anaerobic batch fermentation having different S/I ratios of 0.1, 0.5, 1.0, and 1.5. BMP and anaerobic biodegradabilities ($D_{deg}$) of the wastes were calculated from cumulative methane production data for the tested conditions. At the lowest S/I ration of 0.1, BMPs of piggery blood, intestine residue, and digestive tract content were determined to be 0.799, 0.848, and $1.076Nm^3kg^{-1}-VS_{added}$, respectively, which were above the theoretical methane potentials of 0.539, 0.644, and $0.517Nm^3kg^{-1}-VS_{added}$ for blood, intestine residue, and digestive tract content, respectively. However, BMPs obtained from the higher S/I ratios of 0.5, 1.0, and 1.5 were within the theoretical range for all three types of waste and were not significantly different for the different S/I ratios tested. Anaerobic biodegradabilities calculated from BMP data showed a similar tendency. These results imply that, for BMP assay in an anaerobic reactor, the S/I ratio of anaerobic reactor should be above 0.1 and the inoculum should be sufficiently stabilized to avoid further degradation during the assay.

• 설비공학논문집
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• 제13권5호
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• pp.356-367
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• 2001

A numerical analysis on branch type sparger in drain tank for depressurization is performed to investigate the flow characteristics due to the change of design factor. As the result of this study, sparger\\`s flow resistance coefficient(K) is 3.53 at the present design condition when engineering margin for surface roughness is considered as 20%, and flow ratio into branch pipe ($Q_s/Q_i$) is 0.41. The correlation for calculating flow resistance coefficients as design factor is presented. Flow resistance coefficient is increased as section area ratio of branch pipe for main pipe and outlet nozzle diameter of main pipe decreasing, but the effects of branch angle and inlet flow rate of main pipe are small. As the change rate of ($Q_s/Q_i$)becomes larger, the change rate of flow resistance coefficient increases. The rate of pressure loss has the largest change as section area ratio changing. The condition of maximum flow resistance in sparger is when the outlet nozzle diameter ratio of main pipe ($D_e/D_i$) is 0.167, the section area ratio ($A_s/A_i$) is 0.1 and the branch angle ($\alpha$) is 55^{\circ}$.

• 한국환경농학회지
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• 제35권2호
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• pp.121-127
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• 2016

BACKGROUND: Anaerobic digestion is the most feasible technology because not only the energy embedded in organic matters can be recovered, but also they are stabilized while being degraded. This study carried out to improve methane yield of slaughterhouse wastewater treatment sludge cake by the thermal pre-treatment prior to anaerobic digestion.METHODS AND RESULTS: Slaughterhouse wastewater treatment sludge cake was pre-treated by the closed hydrothermal reactor at reaction temperature of 190℃. BMPs (Biochemical methane potential) of the thermal hydrolysate was tested in the different S(Substrate)/I(Inoculum) ratio conditions. COD(Chemical oxygen demand) and SCOD(Soluble chemical oxygen demand) contents of thermal hydrolysate were 10.99% and 10.55%, respectively, then, the 96.00% of COD was remained as a soluble form. The theoretical methane potential of thermal hydrolysate was 0.51 Nm³ kg^-1-VS_added. And BMPs were decreased from 0.56 to 0.22 Nm³ kg^-1-VS_added when S/I ratio were increased from 0.1 to 2.0 in the VS content basis. Those were decreased from 0.32 to 0.13 Nm³ kg^-1-COD_added when S/I ratio were increased from 0.1 to 2.0 based on COD content. The anaerobic degradability of VS basis have showed 196.9%, 102.2%, 80.7%, 67.4%, and 39.4% in S/I ratios of 0.1, 0.3, 0.5, 1.0, and 2.0, respectively. Also the COD of 119.6%, 76.3%, 70.1%, 69.0%, and 43.1% were degraded anaerobically in S/I ratios of 0.1, 0.3, 0.5, 1.0, and 2.0, respectively.CONCLUSION: BMPs obtained in the S/I ratios of 0.1 and 0.3 was overestimated by the residual organic matters remaining at the inoculum. And inhibitory effect was observed in the highest S/I ratio of 2.0. The optimum S/I ratios giving reasonable BMPs might be in the range of 0.5 and 1.0 in S/I ratio. Therefore VS biodegradability of thermal hydrolysate was in 67.4-80.7% and COD biodegradability showed 69.0-70.1%.

• 전기학회논문지
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• 제61권4호
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• pp.643-649
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• 2012

The diagnosis technique of stator winding faults based on Motor Current Signature Analysis(MCSA) was suggested. Park's vector pattern, the circle that is drawn by d-q transformed currents($i_d$, $i_q$), is widely used for stator winding faults detection. The current Distortion Ratio(DR), defined by the ratio of max axis and min axis of ellipse of Park's vector's pattern, was more simple and powerful method than the Park's vector pattern. In this study, a calculation method of distortion ratio of Park's vector pattern was suggested for auto diagnosis of stator winding short fault and usefulness of suggested calculation method of distortion ratio was verified through simulation using LabVIEW program.

• 한국산학기술학회논문지
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• 제21권10호
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• pp.421-432
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• 2020

본 연구의 목적은 초등학교 고학년 학생의 인터넷 게임 및 스마트폰 이용실태를 파악하고자 하였다. 2018년 10월 6일부터 2019년 9월 30일까지 K 지역 소재 16개 초등학교에 재학 중인 4~6학년 1,618명을 대상으로 자료를 수집하였고, 기술통계와 빈도분석, Chi-square를 이용하여 분석하였다. 연구결과, 인터넷 게임중독 자가진단척도(I-GUESS)는 고위험군이 6.1%로 나타났고, 스마트폰 과의존 척도(S-scale)는 잠재적 위험군 10.1%, 고위험군 0.8%로 나타났다. 인터넷 게임 및 스마트폰 사용과 관련된 신체적 문제는 36.0%가 경험했다고 응답했고, 눈의 피로가 20.4%로 가장 높았다. 정서적 문제는 18.5%에서 경험했다고 응답했으며, 분노가 6.8%로 가장 높았다. 사회적 문제는 21.8%가 경험한 것으로 파악되었고, 부모와의 갈등이 10.3%로 가장 높게 보고되었다. S-scale 점수와 I-GUESS 점수에 따른 주 사용 콘텐츠를 조사한 결과, S-scale 점수와 I-GUESS 점수가 높을수록 중계방송콘텐츠를 가장 많이 사용하는 것으로 나타났다. I-GUESS와 S-Scale 간의 상관관계에서는 I-GUESS와 S-Scale 간의 상관관계에서는 I-GUESS 점수가 고위험군 일수록, S-scale의 고위험군 비율도 높게 나타났으며, S-scale 점수가 고위험군 일수록 I-GUESS 점수의 고위험군 비율도 높은 것으로 나타났다. 향후, 이러한 변수를 고려하여 예방의 관점에서 초등학생을 위한 중재 프로그램 및 부모 교육 컨텐츠 개발이 시급함을 제언코자 한다.