• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.175-184
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• 2012

This study was conducted to develop new mattress systems with vegetation base materials for protecting stream bank and rapid rehabilitation. Vegetation base materials are primarily compounded with fine soil, organic composts and peat moss as plant fibers, a water retainer and a soil improver. Peat moss can usually provide necessary natural fibers and organic materials in soil. Especially, peat moss can absorb up to 25 times its own weight in water and is therefore valued as a water retainer to prevent drying effect of vegetation base materials which can harm the growth of vegetation in mattresses. Normally mattress systems resist the lateral earth pressures or stream power by their own weight. Therefore, filled materials must have suitable weight, compressive strength and durability to resist the loading, as well as the effects of water and weathering. In this project, 100 to 200-mm clean, hard stones were basically specified, and about 50-mm rubbles were also used. Test application of new mattress system carried out in the stream bank of a small stream in the Gwangreung experimental forest, belonging to Korea Forest Research Institute (KFRI) in December 16th, 2006. As a result of the monitoring of vegetation coverage of test application plots (each plot size is 4 by 2 m), the coverage of all plots reached 100% in the end of May, 2007 (approximately 50 days passed after the first gemination of vegetation). The coverage of the plots using big hard stones and organic composts and the plots containing peat moss increased more rapidly. The results show that peat moss is effective to retain soil moisture and establish more sound environment for vegetation gemination.

• Journal of Korea Water Resources Association
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• v.52 no.10
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• pp.743-752
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• 2019

The flow in the meandering channel is characterized by the spiral motion of secondary currents that typically cause the erosion along the outer bank. Hydraulic structures, such as spur dike and groyne, are commonly installed on the channel bottom near the outer bank to mitigate the strength of secondary currents. This study is to investigate the effects of submerged vanes installed in a $90^{\circ}$ meandering channel on the development of secondary currents through three-dimensional numerical modeling using the hybrid RANS/LES method for turbulence and the volume of fluid method, based on OpenFOAM open source toolbox, for capturing the free surface at the Froude number of 0.43. We employ the second-order-accurate finite volume methods in the space and time for the numerical modeling and compare numerical results with experimental measurements for evaluating the numerical predictions. Numerical results show that the present simulations well reproduce the experimental measurements, in terms of the time-averaged streamwise velocity and secondary velocity vector fields in the bend with submerged vanes. The computed flow fields reveal that the streamwise velocity near the bed along the outer bank at the end section of bend dramatically decrease by one third of mean velocity after the installation of vanes, which support that submerged vanes mitigate the strength of primary secondary flow and are helpful for the channel stability along the outer bank. The flow between the top of vanes and the free surface accelerates and the maximum velocity of free surface flow near the flow impingement along the outer bank increases about 20% due to the installation of submerged vanes. Numerical solutions show the formations of the horseshoe vortices at the front of vanes and the lee wakes behind the vanes, which are responsible for strong local scour around vanes. Additional study on the shapes and arrangement of vanes is required for mitigate the local scour.

• Journal of International Academy of Physical Therapy Research
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• v.5 no.2
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• pp.743-751
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• 2014

This study aims to identify the effect of home physical therapy on patients who left the hospital after total knee arthroplasty, compared to the Daily living group, when it was applied to them, under the guidance of physical therapists. As research subjects, 20 patients that were scheduled to leave the hospital after unilateral total knee arthroplasty, were chosen, and they were randomly divided into a home physical therapy group(10 patients) and an Daily living group(10 patients) in order to conduct an experiment. During the 4-week research, home physical therapy was offered for 40 mins once for 5 days a week, and muscular strength, gait components were measured. For muscular strength, quadriceps muscle strength, hamstring muscle strength were measured, and as gait components, endurance, speed, step time, single-limb support were analysed. For this experiment, pre- and post-measurement were performed, and collected data were analyzed using SPSS ver. 18.0 statistical program. From the analysis of data, the following study results were obtained. Home physical therapy group and Daily living group both showed significant improvements in quadriceps muscle strength, hamstring muscle strength, and quadriceps muscle strength, hamstring muscle strength of home physical therapy group more significantly improved than Daily living group's. In relation to gait components, gait endurance, gait speed, step time significantly improved in both of home physical therapy group and Daily living group, whereas home physical therapy group only showed significant improvements in single-limp support. According to the comparison between two groups, gait speed, single-limp support and step time improved more significantly in the home physical therapy group than in the Daily living group. In conclusion, positive results were revealed in both home physical therapy group and Daily living group, with regard to muscular recovery of lower limbs of patients discharged from the hospital after total knee arthroplasty and walking, but considering the comparison results between two groups, it seems that applying home physical therapy is more effective than maintaining a daily life.

• Geomechanics and Engineering
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• v.21 no.1
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• pp.63-71
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• 2020

Strength anisotropy is a typical feature of thin-bedded rock masses and their strength will be degraded subjected to water immersion effect. Such effect is crucial for the operation of hydropower plant because the impoundment lifts the water level of upstream reservoir and causes the rock mass of nearby slopes saturated. So far, researches regarding mechanical property of natural thin-bedded rock masses and their strength variation under water immersion based on field test method are rarely reported. This paper focuses on a thin-bedded stratified rock mass and carries out field test to investigate the mechanical property and strength variation characteristics. The field test is highlighted by samples which have a large shear dimension of 0.5 m*0.5 m, representing a more realistic in-situ situation than small size specimen. The test results confirm the anisotropic nature of the concerned rock mass, whose shear strength of host rocks is significantly larger than that of bedding planes. Further, the comparison of shear strength parameters of the thin-bedded rock mass under natural and saturated conditions show that for both host rocks and bedding planes, the decreasing extent of cohesion values are larger than friction values. The quantitative results are then adopted to analyze the influence of reservoir impoundment of a hydropower plant on the surrounding rock mass stability of diversion tunnels which are located in the nearby slope bank. It is evaluated that after reservoir impoundment, the strength degradation induced incremental deformations of surrounding rock mass of diversion tunnels are small and the stresses in lining structure are acceptable. It is therefore concluded that the influences of impoundment are small and the stability of diversion tunnels can be still achieved. The finings regarding field test method and its results, as well as the numerical evaluation conclusions are hoped to provide references for rock projects with similar concerns.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.10
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• pp.1023-1029
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• 2014

In this paper, we propose an SPDR (Smith Predictor for Disturbance Reduction) scheme to improve the temperature control by reduction of the disturbance in ROT process with measurement delay. The proposed controller is a combination of Astrom's modified Smith predictor with a disturbance reduction controller and a grey predictor. The grey prediction is used to calculate the inverse of the measurement delay and to predict future variations and tendencies of system output. The simulation results demonstrate the successful performance of the proposed disturbance reduction controller and enhance the robustness of the proposed control scheme.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.600-612
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• 2009

Special banks primarily using Internet have different properties in transactions with customers, risk management, capital strength, and branch networks with general banks. The success and failure factors of Internet banks have been explained only by the economies of scale, and learning and experience effects of Internet banks based on the perspective of organizational ecologies. In this study, the success factors of Internet banks are investigated based on strategic choice by organizations and resource-based view of the firms instead of organizational ecology perspective. To this end, 31 major Internet banks operating in overseas market have been classified by the size and profitability of banks, and three strategic groups have been derived. three representative company cases were analyzed. critical success factors of Internet banks were derived, and considerable points when operating Internet banks were discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.6
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• pp.645-653
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• 2021

Biopolymer is a general concept for high molecular compounds produced by living organisms. Among them, the xanthan and β-glucan, which are organic polymer mixture produced by micro-organisms, are mainly used to increase the viscosity of a substance. And diluting in water and mixing with sand or clay can increase compressive strength and shear strength. In this study, mixed soil prepared by mixing soil with xanthan and beta-glucan based biopolymers specially developed for the purpose of increasing soil strength was applied to the river bank revetment, and changes during winter were measured using ground LiDAR. As a result of analyzing winter changes in major sections using three-dimensional point cloud data obtained through ground LiDAR, there were no changes to the extent that it was difficult to confirm with the naked eye in the two sections coated with biopolymer blended soil. However, soil loss due to Rill erosion was confirmed in the natural embankment section where biopolymer blended soil was not used.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.431-440
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• 2013

It was tested in field that a Pull-out Capacity and Shear resistance strength change of reed, common reed and sedge which were planted by mat-type turf and used for revegetation of bank. The testes were done for 9 weeks from end of May and the grasses were planted on sandy soil. Roots grew fastly after planted and increasement of a common reed and sedge root were reduced after 4 weeks but increasement of reed roots were not reduced. The difference of increasement of roots is due to a difference of propagation method. Sedge propagate by seed. Reed and commom reed propagate by seed and subterranean stem and reed has bigger subterranean stem than common reed. So increasement of common reed and sedge roots were slow than reed. By root growth pattern, increasement of pull-out capacity and shear resistance strength showed very similar way of root growth, those of common reed and sedge were fast in early stage of cultivation but were reduced. But increasement of pull-out capacity and shear resistance strength of reed was not reduced. A Maximum shear resistance strength called critical shear resistance strength of common reed and sedge can be Analyzed at 11 weeks after planted.

• Journal of Family Resource Management and Policy Review
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• v.14 no.1
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• pp.37-55
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• 2010

The purpose of this study was to determine the factors affecting family strength and therewith, suggest some strategies to improve family strength and welfare. For this purpose, the researcher sampled 208 college students and surveyed them for their perceptions of the concept of family and family strengths. The results of this study can be summarized as follows. First, as a result of surveying the subjects on their perception of the concept of family, it was found that almost all of them (99%) perceived that 'a family consists of a couple and their children' (item 1). The other items regarding the concept of family chosen by the majority of subjects were 'a couple and adopted child' (item 3 & item 17), 'a remarried couple and their children' (item 9), 'a single parent and children' (item 2), 'a three-generation family; couple, widowed daughter and granddaughter' (item 4), 'three sisters' (item 7), 'an unmarried woman living with a son born from a sperm bank' (item 19), 'a separated couple with no child' (item 13), 'cousins living together' (item 11), 'a divorced man and his girlfriend with child' (item 15) and 'homosexual family' (item 8). Second, as a result of assessing subjects' needs for family functions and their efforts for family strengths, it was found that the family functions for family members scored higher than those for the society, and that subjects' efforts for the family functions conducive to both their family members and society scored lower than their needs for the family functions. Third, subjects' needs and efforts for family functions were positively correlated with family strengths. Namely, family functions were closely related with family strengths.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.21-31
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• 2017

PURPOSES : One of the main components of road projects funded by the Economic Development Cooperation Fund (EDCF) is the improvement or rehabilitation of existing pavements. The result is that pavement structures are critical to the success of a project. There is, however, no design standard available at present that reflects a region's specific features including climate conditions and quality of pavement materials. For this reason, a comparative study of the major EDCF borrowers' flexible pavement design standards was conducted. This study led to the proposal of a new method for applying flexible pavement designs which can be used for EDCF-funded projects in Asia. METHODS : The method has been produced by adjusting some input data of the "AASHTO Interim Guide for Design of Pavement Structures" in accordance with certain Asian countries' geometrical features, tropical and subtropical weather, and strength of pavement materials. The Philippine regional factors, having five different grades, have been selected after taking into consideration the amount of rainfall, strength of pavement materials, and characteristics of the Asia and Pacific regions. Structural layer coefficients have been prepared for two different regions according to the geometric difference between Southeast and Southwest Asia. The Philippine and Sri Lankan coefficients have been used for Southeast Asia and Southwest Asia, respectively. CONCLUSIONS : Owing to applying this new method, it was verified that the thickness of the pavement was underestimated by between 11 cm and 16 cm compared with the originally designed thickness. Having discovered that the use of the Korean and American-oriented factors and coefficients is not appropriate for other Asian countries, the new method is expected to enhance the quality of pavement in future projects.