• ETRI Journal
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• v.43 no.5
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• pp.923-931
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• 2021

We studied the influence of GaAs top-layer thickness on the small-signal modulation response and 56 Gb/s four-level pulse-amplitude modulation eye quality of 850 nm vertical-cavity surface-emitting lasers (VCSELs). We considered the proportionality of the gain-saturation coefficient to the photon lifetime. The simulation results that employed the transfer-matrix method and laser rate equations led to the conclusion that the proportionality should be considered for proper explanation of the experimental results. From the obtained optical eyes, we could determine an optimum thickness of the GaAs top layer that rendered the best eye quality of VCSEL. We also compared two results: one result with a fixed gain-saturation coefficient and the other that considered the proportionality. The former result with the constant gain-saturation coefficient demonstrated a better eye quality and a wider optimum range of the GaAs top-layer thickness because the resultant higher damping reduced the relaxation oscillation.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.23-31
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• 2002

The headway of vehicles entering an intersection is closely related with the saturation flow rate and is a basic parameter required for determining the saturation headway and the start-up lost delay. Since such headway value reflects the drivers' behaviors and features of the intersection, all intersections don't have an equal value, but are affected by number and location of their lanes, changing types, local characteristics and time zone. Accordingly, this study attempted to suggest proper values on the basis of data by investigating headway in lanes. Number of exclusive through lanes was divided into single lane, double lanes and triple lanes, the locations of lanes were divided into inside lane, central lane and outside lane. As a result of investigating the headway, single through lane, double through lanes-inside lane, and triple through lane-outside lane showed as 1.73 sec., 1.71 sec. and 1.93sec., respectively. The result of calculating the area factor of business areas by fixing 1.00 for the residental area and applying relation between headway and saturation flow rate was 0.96. In the case of start-up lost delay lead dual left turn and directional separation were 1.41 sec. and 3.27 sec., respectively, showing the great difference. Therefore, different start-up lost delay according to changing type should be applied.

• Korean Journal of Cognitive Science
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• v.16 no.3
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• pp.189-197
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• 2005

In this study, changes in performance of 2-back task, blood oxygen saturation and heart rate due to $40\%$ concentration oxygen supply were observed. Five male $(25.8\pm1.3)$ and five female $(23.0\pm1.0)$ college students were nked to perform 2-bark task during two types of oxygen (concentration $21\%,\;40\%$) administration. The experimental sequence consisted of Rest1(1 min.), 0-back Task (1 min.), 2-bark Task (2 min.), and Rest2 (4 min.) and the physiological signals such as blood oxygen saturation and heart rate were measured throughout the stages. The experimental result showed that the performance increased significantly at $40\%'s$ concentration of oxygen rather than $21\%'s$, which shows oxygen supply has positive influence on cognitive performance. When $40\%$ concentration oxygen is supplied, the oxygen saturation in the blood increased and heart rate was decreased significantly comparing to $21\%$. It is Suggested that $40\%$ oxygen can stimulate brain activation bY increasing actual blood oxygen concentration in the process of cognitive performance, and hyperoxia makes heart rate decrease.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.29-32
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• 2004

Gaseous partitioning tracer test has been used for determining the volume and spatial distribution of residual non-aqueous phase liquid (NAPL) in the unsaturated soils. In this study, an experimental method for measuring the content of gas-exposed NAPL as well as that of total NAPL in a sand during air sparging was developed. Two different gaseous phase NAPL-partitioning tracers were used; n-pentane, with very low water solubility, was used as the tracer that partitions into NAPL that is only in contact with the mobile gas, and chloroform, with fairly good water solubility, was selected for detecting total NAPL content in the sand. Helium and difluromethanewere used as the non- reactive tracer and water-partitioning tracers, respectively. Using n-decane as a model NAPL (NAPL saturation of 0.018), 25.6% of total NAPL was detected by n-pentane at the water saturation of 0.68. Oniy 9.1% of total NAPL was detected by n-pentane at the water saturation of 0.84. This result implies that the quantity of gas-exposed NAPL increased about three times when the water saturation decreased from 0.84 to 0.68. At the water saturation of 0.68, more than 90% of total NAPL was detected by chloroform while 65.8% of total NAPL was detected by chloroform at the water saturation of 0.84. Considering that the removal rate of NAPL during air sparging for NAPL-contaminated aquifer is expected to be greatly dependent upon the spatial arrangement of NAPL phase with respect to the mobile gas, this new approach may provide useful information for investigating the mass transfer process during air-driven remedial processes fer NAPL-contaminated subsurface environment.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1920-1926
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• 2010

Yoon et $al.^1$ presented an approximate mathmatical model to describe ammonia removal from an experimental batch reactor system with gaseous headspace. The development of the model was initially based on assuming instantaneous equilibrium between ammonia in the aqueous and gas phases. In the model, a "saturation factor, $\beta$" was defined as a constant and used to check whether the equilibrium assumption was appropriate. The authors used the trends established by the estimated $\beta$ values to conclude that the equilibrium assumption was not valid. The authors presented valuable experimental results obtained using a carefully designed system and the model used to analyze the results accounted for the following effects: speciation of ammonia between $NH_3$ and $NH^+_4$ as a function of pH; temperature dependence of the reactions constants; and air flow rate. In this article, an alternative model based on the exact solution of the governing mass-balance differential equations was developed and used to describe ammonia removal without relying on the use of the saturation factor. The modified model was also extended to mathematically describe the pH dependence of the ammonia removal rate, in addition to accounting for the speciation of ammonia, temperature dependence of reactions constants, and air flow rate. The modified model was used to extend the analysis of the original experimental data presented by Yoon et $al.^1$ and the results matched the theory in an excellent manner.

• Korean Parent-Child Health Journal
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• v.8 no.2
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• pp.157-167
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• 2005

The purpose for this study is to identify the effects of nonnutritive sucking and facilitated tucking as a pain management during painful heelstick procedure. This study was a repeated measurement design. Data were collected from Sep. 15, to Oct. 20, 2005. According to the criteria twenty seven high risk infants were selected from the NICU of university hospital. The behavioral state were evaluated with the PIPP(Prematures Infants Pain Profile. PIPP, heart rate, saturation were observed without versus with nonnutritive sucking and tucking care. Statistic analysis was conducted with a wilcoxon nonparametric test. The results of this study were as follows. Pina behavior responses in nonnutritive sucking and tucking cases were lower than without treatment(Z=-4.430, p=.000), Heart rate and heart rate recovery time in nonnutritive sucking and tucking cases were attenuate decrease in heart rate(Z=-2.694, p=.005) and statistical significant differences in periods (Z=-4.229, p=.000). But, Saturation was no significant differences(Z=-3.230, p=.000). In conclusion, the application of nonnutritive sucking and tucking as an pain relieg for high risk infants is nursing intervention in pain management ar heelsticks.

• Journal of Korea Multimedia Society
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• v.18 no.1
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• pp.88-96
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• 2015

The recent increase in the production of 3D contents allowed viewers to experience various 3D contents. However, some of the viewers did not experience 3D depth well. Several researches were done in past to measure viewers' 3D depth perception, but these researches were done with certain limitations. In this paper, we measured viewers' 3D depth perception and recovery rate in relation with the changes in binocular disparities, saturation, and brightness values after subjects' watching 2D/3D contents. The results showed that when viewers watched the 3D content with positive binocular disparities for 42 minutes, viewers felt that the object seemed to have moved further forward than it was before; with 3D content with negative binocular disparities, viewers felt that the object seemed to be moved backwards. We found that the locational differences of the object in positive disparities were greater than those in the negative binocular disparities. The recovery rate was computed by comparing two measured values of before and after watching 3D contents for 30 minutes. On average, after 30-minute break, viewers showed roughly 50 % of recovery rate.

• Journal of Astronomy and Space Sciences
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• v.37 no.2
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• pp.85-94
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• 2020

Equatorial noise, also known magnetosonic waves (MSWs), are one of the frequently observed plasma waves in Earth's inner magnetosphere. Observations have shown that wave amplitudes maximize at the magnetic equator with a narrow extent in their latitudinal distribution. It has been understood that waves are generated from an equatorial source region and confined within a few degrees magnetic latitude. The present study investigates whether the MSW instability and saturation amplitudes maximize at the equator, given an energetic proton ring-like distribution derived from an observed wave event, and using linear instability analysis and particle-in-cell simulations with the plasma conditions at different latitudes along the dipole magnetic field line. The results show that waves initially grow fastest (i.e., with the largest growth rate) at high latitude (20°-25°), but consistent with observations, their saturation amplitudes maximize within ±10° latitude. On the other hand, the slope of the saturation amplitudes versus latitude revealed in the present study is not as steep as what the previous statistical observation results suggest. This may be indicative of some other factors not considered in the present analyses at play, such as background magnetic field and plasma inhomogeneities and the propagation effect.

• Journal of Korea Multimedia Society
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• v.20 no.11
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• pp.1729-1740
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• 2017

This paper describes a vision-based method that effectively recognize a traffic light. The method consists of two steps of traffic light detection and discrimination. Many related studies have used color information to detect traffic light, but color information is not robust to the varying illumination environment. This paper proposes a new method of traffic light detection based on intensity and saturation. When a traffic light is turned on, the light region usually shows values with high saturation and high intensity. However, when the light region is oversaturated, the region shows values of low saturation and high intensity. So this study proposes a method to be able to detect a traffic light under these conditions. After detecting a traffic light, it estimates the size of the body region including the traffic light and extracts the body region. The body region is compared with five models which represent specific traffic signals, then the region is discriminated as one of the five models or rejected as none of them. Experimental results show the performance of traffic light detection reporting the precision of 97.2%, the recall of 95.8%, and correct recognition rate of 94.3%. These results shows that the proposed method is effective.

• Textile Coloration and Finishing
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• v.12 no.6
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• pp.344-352
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• 2000

Two kinds of nylon 6 fabrics with different fiber denier, such as ultramicro fiber(UMF) nonwoven fabric(monodenier 0.05d) and regular fabric(monodenier 2.92d) are dyed with C.I. Acid Red 18(leveling type) and C.I. Acid Blue 113(milling type). Dyeing rates and adsorption isotherms are measured at $60^\circ{C}$, pH 5.0 and at liquor ratio of 1 : 250. To investigate the effect of fixing agents (Matexil FA-SNX, Monorex-RD and Tinofix-ECO) on UMF nylon 6 nonwoven fabric, dyeing is carried out at 3~10% owf with 1 : 2 metal-complex acid dyes, such as Kayalax Navy R(unsulphonated type), Lanasyn Blue S-BL(monosulphonated type) and Kayakalan Black BGL(disulphonated type). The dyeing rate of UMF nylon 6 is faster than that of regular nylon 6. From the results of absorption isotherms, the regular nylon 6 has higher saturation value of Acid Red 18 compared with UMF nylon 6, whereas UMF nylon 6 has higher saturation value of the acid Blue 113. From the absorption isotherms of both acid dyes, the regular nylon 6 has higher saturation value of Acid Red 18, whereas UMF nylon 6 has higher saturation value of the acid Blue 113. The wash fastnesses of UMF nylon 6 increases in the order of metal-complek dye containing nonsulphonated group > monosulphonated group>disulphonated group. Aftertreatment of UMF nylon 6 dyed with unsulponated and monosulphonated dyes improves wash fastness upto grade 1.5, where as that of UMF nylon 6 dyes with disulphonated dye does not improve wash fastness.