• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7A
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• pp.786-793
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• 2004

Autonomous data rate control scheme of current IxEV-DO uplink networks can not supper the various QoS requirements of heterogeneous traffics nor hold rise-over-thermal OtoT) constraints. In this paper, an uplink resource management scheme called the modified weighted g-fair (MWGF) scheduler with RoT filling is proposed and evaluated for heterogeneous traffics in cdma2000 type uplink networks. The proposed scheme belongs to a family of centralized resource management schemes and offers QoS guarantee by using priority metrics as well as lower system loading by holding RoT constraints using RoT filling method. With some case-study simulations, the proposed algorithms shows lower average delays of real time users compared to that of autonomous rate control by 29 - 40 ％. It also shows the 1.0 - 1.3 dB lower received RoT level than autonomous rate control schemes, leading to lower network loading.

• Journal of the Korean Ceramic Society
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• v.12 no.4
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• pp.9-18
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• 1975

Polymer emulsion was used as the admixture for the purpose of increasing the mechanical properties of cement mortar. The effect of polymer emulsion admixture on compressive strength and tensile strength and chemical resistance, relative humidity on compressive and tensile strength, sand particles on water absorption were studied. The results were as follows. 1. Polymer emulson modified mortar cured under 95% of realative humidity showed lower strength than the mortar cured at dry condition. 2. The maximum strength was attained at 10~20% of polystyrene and polyacrylic acid ester polymer-cement mortar. 3. The modified mortar (sand size rate (-9＋35)mech:(-35＋60)mech=4 : 1) was 1.5 times lower than the modified mortar (1 : 1) in water absorption. 4. Compared with the ordinary mortar, the modified mortar showed 2~3 times greater chemical resistance for 5% HCl or 5% H2SO4.

• International Journal of Air-Conditioning and Refrigeration
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• v.10 no.4
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• pp.192-200
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• 2002

A modified asymmetric rectangular fin is analysed using the two-dimensional separation of variables method. This modified rectangular fin is made by attaching the wing on the top side of a rectangular fin. Heat loss from each side of this modified rectangular fin is calculated. The relative increasing ratio of heat loss between a modified rectangular fin and a rectangular fin is presented as a function of dimensionless fin volume, wing height and the location of the wing. Especially, to show the remarkable effect of the wing on the heat loss, the relative increasing ratios of heat loss between two different volume increasing methods are listed.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.84-91
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• 2001

Comparison between performance of a plate fin and that of a modified plate fin is investigated as a function of the position, the non-dimensional width and height of wings as well as the non-dimensional fin length using a two-dimensional separation of variables method. The ratio of the incremental rate of heat loss to that of the area of a modified plate fin is also presented as a function of the height of wings. The modified plate fin is made by attaching the wings to upper and lower sides of a plate fin. One of the results shows that performance of a modified plate fin is more improved as the wings approach left (higher) thermal reservoir.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.17-28
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• 1994

A combined random/reservation multiple access protocol is proposed which can provide services for packet transmission in mobile satellite systems between mobile statons, or between mobile stations and fixed stations. Random multiple access protocol and reservation multiple access protocol which are currently employed in most satellite communication systems have some strengthes and some weeknesses in according to the kind of user and traffic. In this paper, a combined random/reservation multiple access protocol with better characteristics is proposed. The models of the modified random access protocol and the proposed access protocol is setted and analyzed. The performance of the PDAMA protocol, the random access protocol and the proposed access protocol is compared using simulation. For small packet arrival rate, the performance of the proposed access protocol is close at that of the modified random access protocol, and better than that of the PDAMA protocol. As the packet arrival rate is increased, the modified random access protocol is saturated and unstable at 0.23, and the performance of the proposed access protocol is better than that of the PDAMA protocol.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.1
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• pp.61-70
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• 2001

As important factors determining human sensorial comfort, liquid moisture management and surface properties of heat resistant workwear materials were examined. To figure out liquid moisture management properties of the test materials, absorption capacity, rate of absorption, and evaporation properties were assessed. A modified GATS(Gravimetric Absorbency Testing System) was used to measure the liquid moisture accumulation associated with the wicking of liquid moisture from sweating skin. The GATS procedure measures demand wettability of materials to take up liquid in a direction perpendicular to the fabric surface and it was modified to incorporate a special test cell and cover to assess absorption behavior in the presence of evaporation. Fabric stiffness, smoothness, number and the length of surface fibers, and an estimate of the contact area between the skin and fabric surface were measured to characterize the mechanical and surface properties of the test materials. Also an estimate of the force with which a fabric clings to moist skin was made using as wet-cling index.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.139-146
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• 1996

An extended $k-\varepsilon$ tuebulence model modified by considering the streamline curvature effect and standard $k-\varepsilon$ turbulence model have been applied for three dimensional analysis of turbulece flow in a $90^{\circ}$ curved duct. By comparision of the results with the experimental data, the modified extended $k-\varepsilon$ model gave closer agreement with experimental data than the results from standard $k-\varepsilon$ model owing to an extra time scale of the production rate and parameter describing effects of streamline curvature included in the dissipation rate equation.

• Elastomers and Composites
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• v.51 no.2
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• pp.99-105
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• 2016

Alkoxy modified silicone (PAMS) was synthesized from hydroxyl-terminated polydimethylsiloxane (OH-PDMS) and vinyltrimethoxysilane (VTMO) under alkali catalyst (NaOH and KOH) at room temperature ($25^{\circ}C$) via condensation polymerization. Then, the structural verification of the synthesized PAMS was confirmed using $^1H$-NMR and FT-IR spectroscopy. The reaction rate of PAMSs was studied in terms of the concentration variation of alkali catalyst. The reaction rate increased with the concentration of alkali catalyst, but no correlation between conversion and concentration of alkali catalyst was observed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.7-8
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• 2014

Latex-modified concrete using ready mix concrete (R-LMC) was developed for application of building construction project (specifically, the rooftop of a parking garage unable to use heavy equipments for bridge deck overlay) due to three major outstanding properties of R-LMC; bond strength, resistance of cracks at early age, and resistance of freezing and thawing. However, R-LMC at the placement stage is required to be sufficiently cured because R-LMC is very sensitive to rate of evaporation of surface moisture. This study focused on effects of different curing methods and climate condition on cracks on the surface of hardened R-LMC considering the chart of rate of evaporation of surface moisture from concrete provided by American Concrete Institute in manual for placement of latex modified concrete.

• Clinical and Experimental Pediatrics
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• v.65 no.3
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• pp.136-141
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• 2022

Background: High-flow nasal cannula (HFNC) is a noninvasive respiratory support that provides the optimum flow of an air-oxygen mixture. Several studies demonstrated its usefulness and good safety profile for treating pediatric respiratory distress patients. However, the cost of the commercial HFNC is high; therefore, the modified high-flow nasal cannula was developed. Purpose: This study aimed to compare the effectiveness, safety, and nurses' satisfaction of the modified system versus the standard commercial HFNC. Methods: This prospective comparative study was performed in a tertiary care hospital. We recruited children aged 1 month to 5 years who developed acute respiratory distress and were admitted to the pediatric intensive care unit. Patients were assigned to 2 groups (modified vs. commercial). The effectiveness and safety assessments included vital signs, respiratory scores, intubation rate, adverse events, and nurses' satisfaction. Results: A total of 74 patients were treated with HFNC. Thirtynine patients were assigned to the modified group, while the remaining 35 patients were in the commercial group. Intubation rate and adverse events did not differ significantly between the 2 groups. However, the commercial group had higher nurses' satisfaction scores than the modified group. Conclusion: Our findings suggest that our low-cost modified HFNC could be a useful respiratory support option for younger children with acute respiratory distress, especially in hospital settings with financial constraints.