• 상하수도학회지
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• 제14권2호
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• pp.147-156
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• 2000

In this study, the optimal operation parameters of MLE(Modified Ludzack-Ettinger) process treating the liquid supernatant separated from the slurry excreta of swine feedlot was studied as a promising biological treatment process. The nitrogen removal characteristics with different volume ratio between nitrification and denitrification reactor and the operational effect with different nitrogen loading rate, and different C/N($COD_{Cr}/TKN$) ratio were investigated. Based on the laboratory results, pilot MLE plant was operated to examine the effect of ambient temperature for five months including winter. The denitrification reactor which is 20% of total volume was proposed as the most optimal volume fraction for nitrification and denitrification. The optimum ratios of F/M and $F_N/M$ were increased with increase of the C/N ratio. However, optimum F/M ratio was changed more rapidly than $F_N/M$ ratio with increase of the C/N ratio. Therefore, MLE process is desirable to be controlled by F/M ratio in the range of high C/N ratio and by $F_N/M$ ratio in the range of low C/N ratio. Pilot MLE plant showed the higher removal efficiencies of COD and TKN in winter than in summer and was operated most stably at the temperature of $20{\sim}25^{\circ}C$ for mixed liqour.

• 한국지능시스템학회논문지
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• 제12권6호
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• pp.583-588
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• 2002

Recently, Szmidt and Kacprzyk[Fuzzy Sets and Systems 118(2001) 467-477] proposed a non-probabilistic-type entropy measure for intuitionistic fuzzy sets. Tt is a result of a geometric interpretation of intuitionistic fuzzy sets and uses a ratio of distances between them. They showed that the proposed measure can be defined in terms of the ratio of intuitionistic fuzzy cardinalities: of $F\bigcapF^c and F\bigcupF^c$, while applying the Hamming distances. In this note, while applying the Euclidean distances, it is also shown that the proposed measure can be defined in terms of the ratio of some function of intuitionistic fuzzy cardinalities: of $F\bigcapF^c and F\bigcupF^c$.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2002년도 추계학술대회 및 정기총회
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• pp.13-16
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• 2002

Recently, Szmidt and Kacprzyk[Fuzzy Sets and Systems 118(2001) 467-477] Proposed a non-probabilistic-type entropy measure for intuitionistic fuzzy sets. It is a result of a geometric interpretation of intuitionistic fuzzy sets and uses a ratio of distances between them. They showed that the proposed measure can be defined in terms of the ratio of intuitionistic fuzzy cardinalities: of F∩F$\^$c/ and F∪F$\^$c/, while applying the Hamming distances. In this note, while applying the Euclidean distances, it is also shown that the proposed measure can be defined in terms of the ratio of some function of intuitionistic fuzzy cardinalities: of F∩F$\^$c/ and F∪F$\^$c/.

• Geomechanics and Engineering
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• 제37권2호
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• pp.123-133
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• 2024

This study investigates the effects of loading frequency (f) and specimen size on the liquefaction resistance of clean sand. A series of cyclic direct simple shear tests were conducted on Jumunjin sand with varying consolidated relative densities (40% and 80%), f values (0.05, 0.10, and 0.20 Hz), and diameter to height (D/H) ratios (3.63, 3.18, 2.82, and 2.54). The results demonstrated the significant influence of f and D/H ratio on the number of cycles to liquefaction (N_cyc-liq) and the cyclic resistance ratio (CRR₁₅). It was observed that increasing f linearly increased N_cyc-liq. Increasing the specimen height also led to higher N_cyc-liq values irrespective of the f or relative density. Moreover, a positive correlation between CRR₁₅ and f indicated that higher f yielded higher CRR₁₅. This relationship was more pronounced in dense sand than in loose sand. Specimen height also significantly affected CRR₁₅, with increasing the specimen height resulting in higher CRR₁₅ values. Furthermore, the effect of f on CRR₁₅ was less significant compared to the influence of specimen height. The effect of f on the normalized cyclic resistance ratio (NCRR) was relatively negligible for loose sand but more substantial for dense sand depending on the D/H ratio. Data analysis revealed that the NCRR generally decreases as the D/H ratio increases. An interpolation formula was provided to calculate the NCRR based on the D/H ratio regardless of the f and relative density.

• Journal of the Korean Wood Science and Technology
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• 제35권5호
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• pp.67-75
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• 2007

As a part of abating the formaldehyde emission of urea-formaldehyde (UF) resin adhesive by lowering formaldehyde to urea (F/U) mole ratio, this study was conducted to investigate properties of UF resin adhesive with different F/U mole ratios. UF resin adhesives were synthesized at different F/U mole ratios of 1.6, 1.4, 1.2, and 1.0. Properties of UF resin adhesives measured were non-volatile solids content, pH level, viscosity, water tolerance, specific gravity, gel time and free formaldehyde content. In addition, a linear relationship between non-volatile solids content and sucrose concentration measured by a refractometer was established for a faster determination of the non-volatile solids content of UF resin. As F/U mole ratio was lowered, non-volatile solids content, pH, specific gravity, water tolerance, and gel time increased while free formaldehyde content and viscosity were decreased. These results suggested that the amount of free formaldehyde strongly affected the reactivity of UF resin. Lowering F/U mole ratio of UF resin as a way of abating formaldehyde emission consequently requires improving its reactivity.

• 말소리와 음성과학
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• 제4권3호
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• pp.161-169
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• 2012

The purpose of this study was to investigate the characteristics of speech intelligibility of spontaneous speech and the vowel space parameters in patients with Parkinson's disease. Ten PD patients (M=5, F=5) and a corresponding control group of ten normal adults participated in this study. Firstly, subjects were asked to tell a story about their hometown and youth in order to analyze speech intelligibility. Secondly, the subjects were also asked to repeat four vowels (/a/, /i/, /u/, /e/) five times in order to compare their vowel spaces. The results were as follows: (1) the speech intelligibility of the PD group was lower than that of the control group. (2) Four parameters including vowel area, vowel articulatory index, formant centralization ratio, F2i/F1u ratio were significantly different in each group. For instance, vowel area and F2 ratio were wider and higher, respectively. As a result, a decrease in speech intelligibility of patients with PD is likely to show different types of errors from the normal group. The results of this research are meaningful in a sense that they could provide the objective standard of speech intelligibility and vowel space parameters.

• Preventive Nutrition and Food Science
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• 제5권4호
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• pp.230-233
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• 2000

The present work was designed to determine whether change in fluidity of the mitochondrial membrane affects mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics in NIDDM-prone BHE/Cdb rat. Isolated mitochondria fom BHE/Cdb rat fed a 6% coconut oil or corn oil were functionally tested by an analysis of its respiration and the coupling of this process to ATP synthesis in presence of oligomycin, a specific inhibitor of oxidative phosphorylation (OXPHOS), that binds to the {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase. Mitochondria from rats fed coconut oil were more responsive to the inhibitory action of oligomycin with respect to state 3 respiration, respiratory control (RC) ratio and ADP:P (P/O) ratio than were mitochondria from rats fed corn oil. In state 3 respiration, mitochondria from rats fed coconut oil consumed less oxygen than did mitochondria from rats fed corn oil. RC ratio was lower in the mitochondria from rats fed coconut oil than was mitochondria from rats fed corn oil. In P/O ratio, the mitochondria from rats fed coconut oil had a lower P/O ratio than did mitochondria from rats fed corn oil. The data showed that the chang influidity of the mitochondrial membrane by dietary fat affected mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics. The present study on diet differences in {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics provides considerable insight into the role diets play in the control of mitochondrial function, expecially OXPHOS in NIDDM with mitochondrial defects.

• 한국물환경학회지
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• 제21권6호
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• pp.687-694
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• 2005

Lab-scale experiments have been carried out to investigate the effect of F/R ratio of ASBR (Anaerobic Sequencing Batch Reactor) process on the removal of the organic matters in ammonia stripped swine wastewater. Three ASBR inoculated with sludge mixed with granular sludge of UASB (Upflow Anaerobic Sludge Blanket) and anaerobic digested sludge of municipal wastewater treatment plant were operated. Ammonia stripped swine wastewater was used as influent. Prior to conducting the experiments with varied conditions, the effect of increasing organic loading rate from 2.34 to $5.79gTCOD_{Cr}/L$-day at a fixed F/R ratio of 0.1 on the organic removal efficiency has been studied during start-up period. As the result of the experiment, under the condition of varied organic loadings, less than $4.14gTCOD_{Cr}/L$-day, the removed efficiency $TCOD_{Cr}$ of the ASBR process is 83% resulted from the mean value of effluent $TCOD_{Cr}$, 9,125 mg/L during the start-up period. Then ASBRs were operated with F/R ratio of 0.024, 0.303 and 0.91 respectively. Organic loading rate was increased from 4.56 to $15.43gTCOD_{Cr}/L$-day to investigate the effects of F/R ratio and organic loading rate on the organic removal efficiency. As the result of the experiment, less than $6.23gTCOD_{Cr}/L$/L-day, F/R ratio haven't an effect on the organic removal efficiency and the mean removal efficiency of TSS, $TCOD_{Cr}$ and $SCOD_{Cr}$ was about 80%, 86% and 78% at the all of F/R ratio. But as organic loading rate was increased from 8.54 to $12.04gTCOD_{Cr}/L$-day at the F/R ratio of 0.024, the removal efficiency of $SCOD_{Cr}$ decreased from 71% to 63%. The range of decreased removal efficiency of $SCOD_{Cr}$ at the F/R ratio of 0.024 was much more higher than at the F/R ratio of 0.303, 0.91. Thus, as organic loading rate was increased, ASBRs were operated with high F/R ratio to obtain high removal efficiency.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.134-137
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• 2009

본 연구에서는 친환경 추진제인 고농도 과산화수소와 케로신을 사용하는 저추력 이원추진제 로켓 엔진의 O/F ratio에 따른 연소 성능 특성을 파악하였다. 연소시험에 사용된 엔진은 6개의 동축 스월 인젝터로 구성된 멀티 인젝터와 연소실, 노즐로 구성되어있으며, 촉매 점화 방식을 사용하였다. 연소 시험은 O/F ratio 3.8에서 11.0까지 변화시켜가며 수행하였다. 연소 시험 결과를 이용하여 특성 속도($C^*$)와 압력 섭동 값을 계산한 결과, 연소 효율은 O/F ratio 5~6 구간에서 가장 좋았으며 모든 구간에서 연소실 압력대비 압력 섭동 값이 5% 미만으로 안정적임을 확인하였다.

• 한국정보통신학회논문지
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• 제16권5호
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• pp.989-998
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• 2012

본 논문에서는 매우 작은 절대 값을 갖는 펨토 패럿 단위의 커패시턴스를 측정 할 수 있는 비율형 커패시턴스 측정 회로를 제안하였다. 제안한 측정 회로는 스위치 커패시터 적분기와 비교기 그리고 스위치를 제어하는 논리 회로와 카운터로 구성되어 있으며, 측정하고자 하는 커패시턴스와 이미 값이 알려진 온-칩 커패시터간의 비율을 측정하고 그 값을 디지털 신호로 출력한다. 그리고 이 비율 값을 통해 오차가 상당부분 제거된 펨토 패럿 단위의 커패시턴스를 구해낼 수 있다. 제안한 커패시턴스 측정 회로는 표준 CMOS $0.18{\mu}m$ 공정을 사용하여 설계되었으며, HSpice 시뮬레이션에서 5fF 이하의 아주 작은 커패시턴스를 오차율 ${\pm}0.3%$ 이내에서 측정이 가능함을 보였다.