• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.29-37
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• 2017

Compared to the commercial networks, R&E networks have the strength such as flexible network engineering and design. Based on those features of R&E networks, we propose our storage cloud service model which supports general-purpose network users in a central region and experimental network users in distributed regions simultaneously. We prototype our service model utilizing multiple proxy controllers of OpenStack Swift service in order to deploy several regions via experimental backbone networks. Our experiments on the influence of the network latency and the size of data to be transmitted show that the bigger size of data is preferable to the smaller size of data in an experimental backbone network where the network latency increases within 10ms because the rate of throughput decline in the bigger object is comparatively small. It means that our service model is appropriate for experimental network users who directly access the service in order to move intermittently high volume of data as well as normal users in the central region who access the service frequently.

• Wind and Structures
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• v.6 no.1
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• pp.71-90
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• 2003

In recent years, high-strength, light-weight materials have been widely used in the construction of high-rise buildings. Such structures generally have flexible, low-damping characteristics. Consequently, wind-induced oscillation greatly affects the structural safety and the comfort of the building's occupants. In this research, wind tunnel experiments were carried out to study the wind-induced vibration of a building with a tuned liquid column damper (TLCD). Then, a model for predicting the aerodynamic response in the across-wind direction was generated. Finally, a computing procedure was developed for the analytical modeling of the structural oscillation in a building with a TLCD under the wind load. The model agrees substantially with the experimental results. Therefore, it may be used to accurately calculate the structural response. Results from this investigation show that the TLCD is more advantageous for reducing the across-wind vibration than the along-wind oscillation. When the across-wind aerodynamic effects are considered, the TLCD more effectively controls the aerodynamic response. Moreover, it is also more useful in suppressing the acceleration than the displacement in biaxial directions. As s result, TLCDs are effective devices for reducing the wind-induced vibration in buildings. Parametric studies have also been conducted to evaluate the effectiveness of the TLCD in suppressing the structural oscillation. This study may help engineers to more correctly predict the aerodynamic response of high-rise buildings as well as select the most appropriate TLCDs for reducing the structural vibration under the wind load. It may also improve the understanding of wind-structure interactions and wind resistant designs for high-rise buildings.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.37-43
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• 2009

Streaming video service over wireless and mobile communication networks has received significant interests from both academia and industry recently. Specifically, mobile WiMAX (IEEE 802.16e) is capable of providing high data rate and flexible Quality of Service (QoS) mechanisms, supporting mobile streaming very attractive. However, we need to note that streaming videos can be partially deteriorated in their macroblocks and/or slices owing to errors on OFDMA subcarriers, as we consider that compressed video sequence is generally sensitive to the error-prone channel status of the wireless and mobile network. In this paper, we introduce an OFDMA subcarrier-adaptive mobile streaming server based on cross-layer design. This streaming server system is substantially efficient to reduce the deterioration of streaming video transferred on the subcarriers of low power strength without any modifications of the existing schedulers, packet ordering/reassembly, and subcarrier allocation strategies in the base station.

• Journal of Environmental Science International
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• v.24 no.8
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• pp.1037-1043
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• 2015

Since single-use disposable plastic usage has steadily been increasing, recent trends in polymeric research point to increasing demand for eco-friend materials which reduce plastic waste. A huge amount of non-degradable polypropylene (PP)-based pots for seedling culture are discarded for transplantation. The purpose of this study is to investigate an eco-friendly biodegradable material as a possible substitute for PP pot. The blend of poly(lactic acid) (PLA) with poly(butylene adipate-co-terephthalate) (PBAT) was used because of its good mechanical and flexible properties as well as biodegradation. After landfill, various properties of the blend pot were investigated by UTM, SEM, NMR and TGA. The results showed the tensile strength of the blend film rapidly decreased after 5 weeks of landfill due to degradation. From NMR data after landfill, the composition of PLA in the blend was decreased. These results indicate that the biodegradation of the blend preferentially occurs in PLA component. To investigate the effect of holes in pot bottom and side on root growth, a plant in the pot was grown. Some roots came out through holes as landfill period increases. These results indicate that the eco-friendly pot can be directly planted without the removal of pot.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8B
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• pp.1170-1178
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• 2010

Recently as the number of users and application traffic is increasing on high speed network, the importance of application traffic classification is growing more and more for efficient network resource management. Although a number of methods and algorithms for traffic classification have been introduced, they have some limitations in terms of accuracy and completeness. In this paper we propose an application traffic classification based multi-level architecture which integrates several signature-based methods and behavior algorithm, and analyzes traffic using correlation among traffic flows. By strengthening the strength and making up for the weakness of individual methods we could construct a flexible and robust multi-level classification system. Also, by experiments with our campus network traffic we proved the performance and validity of the proposed mechanism.

• Korean Institute of Interior Design Journal
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• v.24 no.5
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• pp.62-69
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• 2015

The purpose of this research is to analyze the methods of the decorations using module plants in interior spaces. This research produced 18 types of the module plant decoration: considering the classifications of module plants(soil, hydroculture, moss), directions of module plants (up, side, down), assembling ways of module plants (horizontal, vertical). Applying these 18 types to the interior space decoration (floor stand, wall attach, ceiling hanging), 54 types were classified. After that, 150 cases of the decoration using module plants in interior spaces were collected and analyzed. In result, the cases were belong to 25 types of 54 types. The important types were the types to be able to decorate wide area of walls or ceilings without occupying floor area: SOIL-UP-VERTICAL, HYDROCULTURE-UP-VERTICAL, MOSS-SIDE-VERTICAL. These types were the decorations with function of bio-filter for air cleaning. Special types were SOIL-SIDE-HORIZONTAL, SOIL-SIDE-VERTICAL with soil developed not to pour and SOIL-DOWN-HORIZONTAL, SOIL-DOWN-VERTICAL with lucks not to pour soil. Plants will be used widely in interior design because of the awareness of eco-friendly design. The strength that module plants are portable, changable, able to exchange parts helps users to maintain plants in interior spaces. For designers, module plants are flexible materials in order to make variety of forms to adjust to interior spaces. The results of this research about methods of the decorations using module plants in interior spaces are useful to designers who want to design interior spaces eco-friendly and user-friendly.

• Journal of the Korean GEO-environmental Society
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• v.20 no.12
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• pp.15-26
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• 2019

This study was conducted to characterize shearing strength of geotextile bag, connecting materials and gabion. A largescale shaking take tests were conducted to assess kinetic characteristics of gabion-geotextile bag retaining wall. Based on the results of large-scale shaking table test, dynamic characteristics of gabion-geotextile bag retaining wall structure against acceleration, displacement, and earth pressure were also analyzed. The increments of dynamic active earth pressure were determined to be (0.376-0.377)H at 1:0.3 slope and $(0.154-0.44)g_n$ earthquake acceleration, and (0.389-0.393)H at 1:1 slope, suggesting that the increments tend to rise as the slope decreases.

• Journal of the Korean GEO-environmental Society
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• v.19 no.12
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• pp.5-14
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• 2018

Recently, method of reinforced earth retaining wall have been proposed according to the material of facing, geosynthetic, construction method, and facing slope. However, the regulations such as the design method and detailed review items according to each construction method are not clear, and collapse due to heavy rainfall frequently occurs. In this study, to obtain a more stable technical approach in the design of reinforced earth retaining wall, the combination of the pullout failure of reinforced earth retaining wall and the optimal reinforcement ratio of height using reinforced earth retaining wall using a single strength reinforcement is assumed, optimum design of stiffener, optimal design of superimposed wall and optimum length ratio of reinforcement material of geosynthetics are proposed through safety factor according to reinforcement length ratio (L/H).

• Geomechanics and Engineering
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• v.24 no.3
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• pp.253-266
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• 2021

The sufficient early strength of primary support is crucial for stabilizing the surroundings, especially for the tunnels constructed in soil. This paper introduces the Steel-Concrete Composite Support System (SCCS), a new support with high bearing capacity and flexible, rapid construction. The bearing characteristics and construction performance of SCCS were systematically studied using a three-dimensional numerical model. A sensitivity analysis was also performed. It was found that the stress of a π-shaped steel arch decreased with an increase in the thickness of the wall, and increased linearly with an increase in the rate of stress release. In the horizontal direction of the arch section, the nodal stresses of the crown and the shoulder gradually increased in longitudinally, and in the vertical direction, the nodal stresses gradually decreased from top to bottom. The stress distribution at the waist, however, was opposite to that at the crown and the shoulder. By analyzing the stress of the arch section under different installation gaps, the sectional stress evolution was found to have a step-growth trend at the crown and shoulder. The stress evolution at the waist is more likely to have a two-stage growth trend: a slow growth stage and a fast growth stage. The maximum tensile and compressive stresses of the secondary lining supported by SCCS were reduced on average by 38.0% and 49.0%, respectively, compared with the traditional support. The findings can provide a reference for the supporting technology in tunnels driven in loess.

• Fashion & Textile Research Journal
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• v.23 no.1
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• pp.106-117
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• 2021

This study proposes a design process for an upper limb assistive wearable soft robot that will enable the development of a clothing product for an upper limb assistive soft robot. A soft robot made of a flexible and soft material that compensates for the shortcomings of existing upper limb muscle strength assistive devices is being developed. Consequently, a clothing process of the upper limb assistive soft robot is required to increase the possibility of wearing such a device. The design process of the upper limb auxiliary soft robot is presented as follows. User analysis and required performance deduction-Soft robot design-upper limb assistive wearable soft robot prototype design and production-evaluation. After designing the clothing according to the design process, the design was revised and supplemented repeatedly according to the results of the clothing evaluation. In the post-production evaluation stage, the first and second prototypes were attached to actual subjects, and the second prototype showed better results. The developed soft robot evaluated if the functionality as a clothing function and the functionality as the utility of the device were harmonized. The convergence study utilized a process of reducing friction conducted through an understanding and cooperation between research fields. The results of this study can be used as basic data to establish the direction of prototype development in fusion research.