• Phonetics and Speech Sciences
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• v.12 no.2
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• pp.17-27
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• 2020

This paper examines kinematic characteristics of /pk/ clusters, as compared to /kk/ and /pp/ with varying vowel contexts and speech rate. The results of EMMA data from eight Seoul-Korean speakers indicate as follows. Firstly, comparing /pk/ to /pp/ sequences, lips closing movement was faster and spatially greater in the /a/-to-/a/ context while temporally longer in the /i/-to-/i/ context. It was smaller in spatial displacement and shorter in temporal duration in /pk/ sequences. Peak velocity did not vary. Secondly, comparing /pk/ with /pp/ and /kk/ controls, lip aperture was less constricted in the /a/-to-/a/ context than /i/-to-/i/, but the maximum contact between the upper and lower lips was invariant across different vocalic contexts within /pk/ sequences (/apka/=/ipki/). Categorical reduction of C1 in /pk/ sequences fell in with the low-vowel and fast-rate conditions with across-/within-speaker variability. Gradient reduction of C1 was observed in all C1C2 types, being more frequent in fast rate. Lastly, the jaw articulator was a stable indicator of rate effects. The implication of the current study is that gestural reduction occurs with categorical reduction and general spatiotemporal weakening in the assimilating contexts, while quantitative properties of gestures may be a reason for gradient reduction, not necessarily confined to place assimilation.

• KIEAE Journal
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• v.11 no.2
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• pp.3-8
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• 2011

This study was carried out for analysing the relationship of environmental factors and the reduction rate of land compensation of six urban development projects near waste landfill sites located in the Seoul metropolitan area. For a close investigation, 24 variables were selected but only 4 environmental variables were identified to have high correlation to the reduction rate of compensation. These are fine particles(PM10), bad smell, the ratio of a greening zone of land and park, and the distance in straight line from the landfill site. Two variables-PM10 and bad smell-were found to have an effect on the average reduction rate of land compensation by correlation analysis. On the other hand, the ratio of a greening zone and the distance in straight line from the landfill site have been rejected for the significance test. The result of regression analysis of six models for the search of affecting variables on the reduction rate of compensation is that PM10 and bad smell have the impact ratio of more than 0.5. But the ratio of greening zone and the distance from the landfill are not significant factors, having the impact ratio of 0.025~0.045 except one model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.8-13
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• 2020

Seamless pipes are fabricated by drilling a hole in a cylindrical material and drawing the material to the desired diameter. These pipes are used in environments where high reliability is required. In this study, the pipe drawing process was simulated using DEFORM, a commercial finite element method (FEM) analysis program. The outer diameter of the steel cylinder used herein before drawing was 70 mm, and the target outer diameter was 58 mm. The drawing process consisted of two stages. In this study, the effect of cross-sectional reduction rate on the pipe was investigated by varying the cross-sectional reduction rate in each step to achieve the target outer diameter. The results of this study showed that the first section reduction rate of 26% and the second section reduction rate of 13.9% caused the lowest damage to the material. Moreover, the FEM simulation results confirmed the influence of the drawing die angle on the pipe drawing process. The drawing die angles of 15° in the first step and 9° in the second step caused the least damage to the material.

• Textile Coloration and Finishing
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• v.16 no.2
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• pp.25-33
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• 2004

Melange yams were prepared by varing the ratio of raw cotton dyed with Indigo, Gardenia and Sappan wood colorants, respectively. The antibacterial activity and deodorization on melange yarns were evaluated for bacteria reduction rate and deodorization rate. The bacterial reduction rate on melange yarns was explored with Staphylococcus aureus, Klebsiella pneumoniae. The melange yarns on the ratio of raw cotton dyed with Sappan wood and Indigo showed high Staphylococcus aureus reduction rate of 99% and 90%, regardless of Al-mordanting treatment, but those with Gadenia hardly showed bacteria reduction rate. The melange yarn showed high Klebsiella pneumoniae reduction rate of 99% for Al-mordanting treatment with Sappan wood. The others were poor. The deodorization of 81% and 98∼99% obtained with melange raw sliver and melange sliver dyed with Indigo, Gardenia and Sappan wood colorants, but dyeing did not significantly affect deodorization rate.

• Journal of Powder Materials
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• v.31 no.2
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• pp.163-168
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• 2024

As the demand for lithium-ion batteries for electric vehicles is increasing, it is important to recover valuable metals from waste lithium-ion batteries. In this study, the effects of gas flow rate and hydrogen partial pressure on hydrogen reduction of NCM-based lithium-ion battery cathode materials were investigated. As the gas flow rate and hydrogen partial pressure increased, the weight loss rate increased significantly from the beginning of the reaction due to the reduction of NiO and CoO by hydrogen. At 700 ℃ and hydrogen partial pressure above 0.5 atm, Ni and Li₂O were produced by hydrogen reduction. From the reduction product and Li recovery rate, the hydrogen reduction of NCM-based cathode materials was significantly affected by hydrogen partial pressure. The Li compounds recovered from the solution after water leaching of the reduction products were LiOH, LiOH·H₂O, and Li₂CO₃, with about 0.02 wt% Al as an impurity.

• ETRI Journal
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• v.34 no.3
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• pp.470-473
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• 2012

In this letter, the constant driving power reduction ratio has been achieved for column drivers regardless of the input image by incorporating a new static power reduction scheme into the previous dynamic power reduction method. The measured power reduction ratio is around 50% for a 120 Hz liquid crystal display panel in such cases of still input video and fallback.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.255-258
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• 2009

Leading developed countries have studied energy self-sufficient houses such as zero or low energy buildings to reduce energy consumption for buildings since the early 1990s. Moreover, some developed countries have actually constructed self-sufficient houses and operated them for demonstration, expanding use of such houses. Korea has also established Zero Energy Solar House(ZeSH) and studied energy independence. Therefore, this study analyzed research result regarding ZeSH, self-sufficient energy house hold of Korea, found out technologies used for heating energy independence, used building interpretation program(ESP_r) to evaluate performance of each factors and analyzed energy reduction quantitatively. Results from the research are as follows: Reduction rate of actual detached house's heating load was also analyzed quantitatively depending on application of each technology. When each factor was applied step-by-step, annual reduction rate of heating load depending on increase in insulation thickness reached 6.6~22.2 %. Annual reduction rate of heating load depending on increase insulation thickness, and change in window heating performance and area ratio reached 31.5 %. Annual reduction rate of heating load through high-sealing and high-insulation depending on change in leakage rate reached 40.0~88.9 %. Annual reduction of heating load, when Mass Wall and attached sun space was applied were applied reached 28.5~39.2 %, respectively.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.72-77
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• 2019

Soil type in LID infiltration practices plays a major role in runoff reduction efficacy. In this study, the effects of infiltration rate of foundation ground under bioretention on annual runoff reduction rate was evaluated using LIDMOD3 which is a simple excel based model for evaluating LID practices. A bioretention area of about 3.2 % was required to capture surface runoff from an impervious area for a 25.4 mm rainfall event. The relative error of runoff from bioretention using LIDMOD3 is 10 % less than that of SWMM5.1 for a total rainfall event of 257.1 mm during the period of Aug. 1 ~ 18, 2017, hence, the applicability of LIDMOD3 was confirmed. Annual runoff reduction rates for the period 2008 ~ 2017 were evaluated for various infiltration rates of foundation ground under the bioretention which ranged from 0.001 to 0.600 m/day and were converted to annual runoff reduction for hydrologic soil group. The runoff reduction rates within hydrologic soil group C and D were steeply increased through increased infiltration rate but not steep within hydrologic A and B with reduction rates ranging from 53 ~ 68 %. The estimated time required to completely empty a bioretention which has a storage depth of 0.632 m is 3.5 ~ 6.9 days and we could assume that the annual average of antecedent rainfall is longer than 3.5 ~ 6.9 days. Therefore, we recommended B type as the minimum hydrologic soil group installed LID infiltration practices for high runoff reduction rate.

• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.11
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• pp.1174-1185
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• 2012

This study develops tight-fitting upper clothing to measure electrocardiography (ECG) data. Taking into consideration the elasticity of the clothing, we made 4 experimental clothes by applying to each a weft reduction rate of 40%, 50%, 60%, and 70%. The 4 experimental clothes were used to measure resting ECG, exercise ECG, and post-exercise ECG for 4 men in their 20s. We compared clothing pressures using sensors on the human body and on a dressform. Subjective wear sensations of the 4 experimental clothes were evaluated using a subjective 7-point scale (with 7 being most excellent). We measured clothing pressures by using the air type pressure (AMI 3037-2) for upper and lower chest sensors in the developed tight-fitting upper clothing. The lower chest sensor showed that the clothing pressure on a human body and dressform changed consistently as the weft reduction rate decreased. The upper chest sensor showed inconsistent changes in clothing pressure as the weft reduction rate decreased. The wearing-test result for preliminary subjects showed that the lower chest sensor was more stable than the upper chest sensor; therefore, we inserted the sensor at the lower chest position before performing ECG. Except for Subject 4, the resting ECGs were stably measured for 3 subjects (Subject 1, Subject 2, and Subject 3) in all the developed clothes (A clothing, B clothing, C clothing, and D clothing). However, D clothing showed stable ECG values after exercise. The results of the experiment showed that we could measure ECG without difficulty using clothes with a weft reduction rate of 40% when the movement was not intense; however, tight-fitting upper clothing with a weft reduction rate of 70% was necessary to measure exercise ECG and post-exercise ECG values.

• Journal of the Korean Home Economics Association
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• v.36 no.6
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• pp.85-94
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• 1998

In this study we tested the physiological influence on human-body according to clothing pressure with reduction rate and varied posture using three kinds of belt with different width. The width of belts were 2.5cm, 3.5cm and 4.5cm, and reduction rates of belts were 0%, 2.5% and 5% of the subject/s waist size respectively. the measured postures were standing state and sitting stste in the chair. The reasults are as follows; 1. Clothing pressure was high in the order of Side part>Front part>Back part and the rate fo change in the side part was highest, according to the reductio rate of belts. The more the width of belt was wide, the less the clothing pressure was small, and this kind of phenomenon could be explained by "The Principle of the power". 2. Both the rate of reduction of belt and the change of average skin temperature in accordance with the width of belt is small, however, the more the width of belts is wider and the reduction rate is bigger, the more the skin temperature at the waist part is increased. 3. The blood pressure and pulse was influenced when the width of belt was narrow and the reduction rate was high. 4. A sense restraining was much influenced by the width of belt, especially when the width of belts was wide, the significant difference was permitted.permitted.