• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.311-316
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• 2001

This study analyzed the influence of paste fluidity and vibration time for fundamental properties of porous concrete. Results of this study were shown as follows; 1) Even if target void ratio is same, void ratio and compressive strength of porous concrete is different according to w/c, paste flow and vibration time. So, In case of target void ratio, we must consider the influence of w/c, paste flow, and vibration time. 2) Though w/c and vibration time are same, as paste flow increase, all void ratio, continuous void ratio, and compressive strength decrease and difference between upper and lower void ratio increase. 3) Though w/c and paste flow are same, as vibration time increase, all void ratio and continuous void ratio decrease and difference between upper and lower void ratio increase. Also, compressive strength increase by 10 seconds and decease after 10 seconds. 4) As types of superplasticizer is different, all void ratio, continuous void ratio, and compressive strength are different. So, we must give consideration to paste fluidity and vibration time in order that increase of strength of porous concrete and distribution of uniform void.

• Food Science and Preservation
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• v.8 no.2
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• pp.157-163
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• 2001

Optimal conditions for hot water extraction of Liriope spicata tuber were investigated with changes in solvent ratio(2∼6 fold) and heating time(1∼5 hr) by response surface methodology. The content of extractable solids increased with an increased in solvent ratio, and the highest content showed at heating time of 3 hr. The content of total steroid saponin increased with a decrease in solvent ratio, and increased with an increase in heating time at increasing the solvent ratio. The content of non-reducing sugar containing oligosaccharides at a lower solvent ratio didn’t show changes depending on heating time, while that at a higher ration decreased with an increase in heating time. Optimal extraction conditions using hot water as the limited conditions of 15∼18% extractable solids, 1.5∼2.0% total steroid saponin, 6∼8% reducing sugar, 6∼7% non-reducing sugar and 13∼15 brix were 3 hrs of heating time and 4 fold of solvent ratio.

• Journal of Environmental Science International
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• v.13 no.7
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• pp.675-680
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• 2004

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

• The Journal of Korean Medicine
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• v.18 no.1
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• pp.143-156
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• 1997

This report was conducted to quantify the pulse/respiration ratio and set up the normal range of wan-maeck(緩脈). In order to objectify the pulse diagnosis and use as basic clinical index of Cold-Hot diagnosis, we developed the hardware and software for detection and interpretation of pulse/respiration ratio, pulse/expiration ratio, pulse/respiration ratio, inspiration time, expiration time, respiration frequency, respiration time, duration of one pulse and pulse and pulse rate per minute, The results were as follows; pulse/respiration ratio is $4.30{\pm}1.03$ times, pulse/respiration ratio is $1.60{\pm}0.32$ times, pulse/respiration ratio is $2.37{\pm}0.75$ times, inspiration time is $1.35{\pm}0.20$ sec, expiration time is $1.89{\pm}0.39$ sec, respiration frequency is $17.16{\pm}3.49$ times/min, total respiration time is $3.63{\pm}0.71$ sec, duration of a pulse is $0.86{\pm}0.15$ sec, pulse rate is $71.51{\pm}12.30$ times/min.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.299-303
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• 1986

To provide useful information on the improving cultural practices of mungbean, investigations were made on Ca/Mg and (equation omitted) ratio in soil and plant grown under three fertilizer levels of N, P, K with different upland soils, using variety, Kyonggijaerae 5. Highly significant possitive correlations were observed between the soil extracted molar Ca/Mg ratio, (equation omitted) ratio at flowering time and yield, number of pods per plant, respectively. Soil-extracted Ca/Mg ratio at flowering time ranged from 1.9 to 6.4 and (equation omitted) ratio ranged from 0.17 to 0.33. Yield decreased rapidly as extracted soil Ca/Mg ratio became smaller than the ratio of 3.9, and yield was the highest the (equation omitted) ratio adjusted to 0.23 at flowering time. At harvesting time, Ca/Mg ratio in plant ranged from 1.4 to 4.3 and the yield decreased rapidly as Ca/Mg ratio in plant became smaller than 2.6. Yields, however, were not related to the soil-extracted Ca/Mg ratio interval from 3.9 to at least 6.4 in flowering time and Ca/Mg ratio in plant ranged from 2.6 to 4.3 at harvesting time.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.1
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• pp.101-108
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• 1997

The initial token value required to the optimal performance of discrete event systems can be decided by Sum of Delay Time and Synchronic Time ratio, which are new synchronic variables in Timed Place Petri Nets. For the system consisting of two Live-and-Bounded circuits(LB-circuits) fused in common Transition-Transition-Path or common Place-Place-Path, we prove that the Synchronic Time Ratio is the initial token ratio between two LB-circuits to optimally perform system functions. These results are generalized and formulated as a theorem. The initial tokens of a specific place can imply shared resources. Using the theorem, we can decide the minimum number of the shared resources to obtain the optimal performance, and minimize the idling time of resources. As an example, an automated assembly system is modeled by Timed Place Petri Net, and the initial tokens to achieve the optimal system performance are identified. All the values are verified by simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.169-173
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• 2009

We studied driving characteristics according to the ratio of mass and charging (m/q) value for charged toner particles with black and yellow color in charged particle type display panel. After biasing rectangle pulse to the transparency electrodes of putted panel with toner particles, its response time and contrast ratio are simultaneously measured using a laser as a optical source, photodiode as a detector and reflective system. As a results, contrast ratio is largest at the shortest response time region which is different to the particle because of m/q. We proposed relational equation for response time, m/q, cell gap and biasing voltage. It has not been studied and reported to analyze the relationship of response time, biasing voltage, lumping phenomena, cell gap, and contrast ratio for toner particle type display.

• Journal of the Korean Society of Safety
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• v.18 no.1
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• pp.71-75
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• 2003

The purpose of this study was to review the factors that influence on the combustion experiment of oxidizing solid such as mixing ratio of oxidizing solid and combustible support content ratio of oxidizing solid, ambient temperature, maturing time, combustible support, and additives. The 30g mixing compound samples of oxidizing solid and combustible support were tested with different mixing ratios. As a result, the Infest burning time was measured when mixing ratio was 4 (oxidizing solid) : 1 (combustible support). And the burning time was decreasing as the ambient temperature and maturing time were increasing.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1347-1350
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• 2005

A modified Time-Ratio Gray Scale AMOLED drive technique is described in which the frame period is split into two half-frames, each of which is divided into binary weighted sub-frames and driven in the conventional time-ratio manner. The proposed technique improves aperture ratio by reducing TFT sizes in pixel circuits.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.823-831
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• 2008

Since it needs the light computational load and small database, sound source localization method using time delay of arrival(TDOA method) is applied at many research fields such as a robot auditory system, teleconferencing and so on. Researches for time delay estimation, which is the most important thing of TDOA method, had been studied broadly. However studies about factors for time delay estimation are insufficient, especially in case of real environment application. In 1997, Brandstein and Silverman announced that performance of time delay estimation deteriorates as reverberant time of room increases. Even though reverberant time of room is same, performance of estimation is different as the specific part of signals. In order to know that reason, we studied and analyzed the factors for time delay estimation using speech signal and room impulse response. In result, we can know that performance of time delay estimation is changed by different R/D ratio and signal characteristics in spite of same reverberant time. Also, we define the performance index(PI) to show a similar tendency to R/D ratio, and propose the method to improve the performance of time delay estimation with PI.