• Journal of the Society of Disaster Information
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• v.9 no.4
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• pp.429-438
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• 2013

In this study, compare and analyze for high-rise evacuation safety design criteria improvement about internal high-rise building egress safety rule. To the result, high-rise evacuation safety design criteria improvement data can be summarized as follows. First, should compute the evacuation capacity about the number of persons and when more than 2 exits are requested, over 50% of evacuation capacity must be satisfied even approaching to 1 exit is unable. Second, 2 ways of evacuation can be made smoothly by the stair or exit separation-distance standard regulation. Third, regulate the length limitation of dead-end corridor or passageway and it should give grades in limitation of whether the spring-cooler has been installed. Fourth, must secure the evacuation way and do the evacuee guidance when it's safety area and elevator or stair. Also needs to provide extra safety area to secure horizontal direction Escape Safety except fire escaping floor.

• Journal of the Korean Wood Science and Technology
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• v.18 no.4
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• pp.26-40
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• 1990

The plane trees(Platanus occidentalis L.) have been grown in Korea very widely as ornamental garden or street trees but they have not been used as manufacturing materials The proportion of imported wood has been now over 85% of raw materials needed in the wood industry, and therefore, many of studies on the substitution of domestic wood for imported wood and on the increasing the utilization rate of domestic species have been attempted and considered as very important projects to solve. From a this point of view, this study was carried out to investigate solid wood bending properties of plane trees and then to develop their end-uses, and the size of specimens tested was $15\times15\times350mm$ for steaming treatment and they were dried to $15\pm1%$ before bending. The results obtained were as follows: 1. The optimum conditions for solid wood bending processing of Platanus occidentalis are showed in Table 7. 2. The minimum solid-bending radii of Platanus occidentalis were 40mm in steaming treatment. 3. The effect of knots, diagonal grain and decay on the degradation of bending processing properties were very severe. 4. The bending stress was setted successfully through $80^{\circ}C$-15hrs drying after bending and the spring back for 24hr-exposing time was only about 1%.

• Physical Therapy Rehabilitation Science
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• v.9 no.3
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• pp.197-200
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• 2020

Objective: The purpose of this study was to develop and investigate the feasibility of a sit-to-stand assistive chair using a pneumatic cylinder. Design: Cross-sectional study. Methods: The sit-to-stand assistive chair was developed to assist the sit-to-stand movement by rising up of the chair by a pneumatic cylinder. After the user is seated on the chair, if the pneumatic cylinder pulls the seat plate when standing up, the spring of the pneumatic cylinder, which has been stretched, assists in rising the rear end of the seat plate so that the user can stand conveniently and comfortably. A feasibility test was performed in 10 heathy adults. The electromyographic muscle activation of the trunk and lower extremity muscles was analyzed, which included the erector spinae, rectus abdominis, quadriceps, tibialis anterior, gastrocnemius when standing up from sitting using the developed chair and standing up without using the developed chair. Results: As a result, the sit-to-stand assistive chair using a pneumatic cylinder was developed. In the feasibility test, the use of the developed chair had a decrease in rectus abdominis, quadriceps, tibialis anterior activation compared to those who did not use the device in the healthy adults. Conclusions: The sit-to-stand assistive chair using a pneumatic cylinder may be helpful to reduce the activation of the rectus abdominis, quadriceps, tibialis anterior muscles when performing a sit-to-stand movement. Through the results, the efficacy of the sit-to-stand assistive chair can be confirmed. In the future, further studies are warranted to investigate for the safety and efficacy of its use in the elderly population or those who are disabled.

• Journal of Korean Society on Water Environment
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• v.36 no.1
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• pp.1-13
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• 2020

The purpose of this study was to investigate the thermal and chemical stratification in Lake Paldang 2013-2018 weekly using Schmidt's stability index (SSI) and the index of chemical stratification (IC-i). The annual average for SSI was 19.1 g cm/㎠ with the maximum value of 45.3 g cm/㎠ in the summer and the minimum value of 4.8 g cm/㎠ in fall-winter showing seasonal differences as well as increased vertical mixing in the summer. The lake stability increased higher in 2016 as compared with the other period. The most influential factors of thermal stratification were temperature and heavy rainfall. Especially, high water temperature and a prolonged residence duration caused by reduced rainfall and inflows could result in an increase of the stratification period. While decreasing inflow and outflow at the end of the rainfall, the thermal stratification was restrengthened within 7-14 days, and then stabilized rapidly before the rainfall. IC-DO increased with high air temperature in the spring and fall-winter. However increasing sunshine duration and residence time and decreasing rate of outflow caused an increase of IC-DO in the summer. Rainfall (less than 800 mm/year) and discharge (less than 200 CMS) significantly declined in 2015 resulting in IC-DO (0.77) increased more than three times over the other years and bottom water hypoxia occurred. The SSI and IC-i used in this study could be applied to other lakes to understand changes in stratification and mixing dynamics.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.387-401
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• 2016

This paper takes a half-through steel truss arch bridge as an example. A seismic analysis is conducted with nonlinear finite element method. Contrast models are established to discuss the effect of simplified method for main girder on the accuracy of the result. The influence of seismic wave direction and wave-passage on seismic behaviors are analysed as well as the superstructure and arch ring interaction which is mostly related with the supported bearings and wind resistant springs. In the end, the application of cable-sliding aseismic devices is discussed to put forward a layout principle. The main conclusions include: (1) The seismic response isn't too distinctive with the simplified method of main girder. Generally speaking, the grillage method is recommended. (2) Under seismic input from different directions, arch foot is usually the mostly dangerous section. (3) Vertical wave input and horizontal wave-passage greatly influence the seismic responses of arch ring, significantly increasing that of midspan. (4) The superstructure interaction has an obvious impact on the seismic performance. Half-through arch bridges with long spandrel columns fixed has a less response than those with short ones fixed. And a large stiffness of wind resistant spring makes the the seismic responses of arch ring larger. (5) A good isolation effectiveness for half-through arch bridge can be achieved by a reasonable arrangement of CSFABs.

• Korean Journal of Childcare and Education
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• v.9 no.5
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• pp.181-200
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• 2013

This study aimed at exploring how an instructor constructs meanings through content-based instruction (CBI) offered to pre-service teachers majoring in early childhood education. The course, early childhood mathematics education, was conducted during the spring semester in 2011. This study adopted a narrative inquiry, and data were collected through observations, interviews, and work samples. This study found that during the whole process from the preparation phase to the end-of-program evaluation, the instructor captured diverse challenging moments. During the preparation phase, she needed to have careful orchestration in designing lessons in order to overcome her feeling of pressure as a non-native speaker of English and design the integration of contents and English language learning to be truly powerful. In the phase of implementation, the lack of student motivation and building a good rapport between the instructor and the students were certainly challenges. The result of the student evaluations weakened her desire to implement CBI. The instructor incorporated diverse instructional strategies to overcome the obstacles. The instructor's experiences in this study will positively shape future educators' thinking and learning about meaningful and appropriate academic English instruction for content-area teaching of college students who were majoring in early childhood education.

• Preventive Nutrition and Food Science
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• v.15 no.3
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• pp.229-232
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• 2010

Caffeine and catechins from the Yabukita, Yutakamidori, Saemidori, Okumidori, and Fushun varieties of tea leaves picked during different harvesting seasons from April to October were evaluated using HPLC. Total content of catechins increased greatly with the later harvesting time of tea leaves (i.e., picking the leaves in September versus in April) and decreased slightly after September. Yabukita tea leaves picked in August contained 43.1 mg% catechins including EGC, EC, ECG, and EGCG, with the ECGC levels constituting greater than 50% of those four compounds. Yutakamidori and Okumidori varieties picked in September contained the highest catechin values, at 43.6 mg% and 31.0 mg%, respectively. Fushun and Saemidori varieties contained lower catechin concentrations of 14.5 mg% (July) and 11.7 mg% (August) compared to other varieties. The EGCG levels gradually decreased in the late harvesting season, while levels of the other catechins, EC, EGC, and ECG, gradually increased. All varieties of green tea showed a gradual decrease in caffeine content toward the end of our harvesting efforts in October, with levels of 58～68 mg% in April and 28～57 mg% in October. Yabukita, Saemidori, and Okumidori varieties reached their highest caffeine levels in late spring/early summer, with Yabukita and Okumidori varieties reaching a high of 73.4% and 63.5% caffeine, respectively, in May, and Saemidori at 64.0% in June. In particular, Fushun still contained high caffeine of 66.8 mg% (September) during the late harvesting season.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.81-86
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• 1996

Subsea pipelines have an important role in the overall tasks of offshore oil and gas production but arc exposed to various hazards with high potential risks of damage resulting in serious economic loss and impact on ocean environment. In this paper, the dynamic free span is analysed, which is one of main risk factors against the safety of subsea pipelines and the allowable length of dynamic free span which is important for the design of subsea pipelines is determined. The allowable free span length is examined by considering the relationship between vortex shedding frequency and natural frequency of pipeline free span, and the variation of the allowable length is analysed for different boundary conditions of pipe ends. The free span is regarded as a beam on elastic foundations and the boundary condition of the beam is generalized by modelling as restrained by linear and rotational spring at each end. A non-dimensionalized curve is obtained to facilitate the determination of exact allowable length of dynamic free span for subsea pipelines and is applied to the pipelines which is to be installed in the gas fields of the south of East Sea of Korea.

• Journal of the Korean Institute of Landscape Architecture
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• v.15 no.3
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• pp.11-19
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• 1988

The purpose of this study is to investigate ways to control the wind dispersal of contton-wrapped seeds of such poplars and willows as Poplus alba, P. tomentiglandulosa, P. euramericana, P. deltoides, and Salix pseudo-lasiogyne. These trees are hated by many people because of their seeds blowing all over the place during May. These cottony seeds can be nuisance to various types of outdoor activities, pose safely threat to drivers, become fire hazards during prolonged spring dry spells, and cause many types of health hazards of allergy such as sneezing. rhinitis, asthma, and skin rashes. Four control methods can be used to resolve the problem. First, pruning can be a solution, but it is unsatisfactory in terms of costs and outcome. Second, planting of male trees only can be a solution, but it is hard to identify sexes of saplings. Third, female trees can he replaced with other species. But it requires high costs and takes at least ten years to functionally replace the removed ones. As an alternative to such unsatisfactory control methods, the possibility of applying plant growth regulators has been investigated since 1983. During the pre-test, various concentrations and mixtures of them were either sprayed or injected, but failed to achieve any promising results. But the injection of a mixture made up of 0.75g of 2-chloroethane phosphonic acid with 0.2 mg of GA in 300cc water in the end of March produced premature falling of almost all aments and capsules of treated poplars and willows. It was found that the effect of the injection lasts two years. The results of the main experiment of 1987 can be summarized as follows ; First, the injection of the mixture of 2-chloroethane phosphonic acid and GA increases the premature abscisin of aments and capsules, thus reducing the wind dispersal of the cottony seeds of S. pseudolasiogyne, P. tomentiglandulosa, and P. euramericana 1644.09, 1200.61, and 1485.11 times, respectively, than that of the naural abscisin, It is estimated that the average number of wind-blown seeds reduced are approximatively 6,185,100, 4062,900, and 2,830,670 per tree, respectively. Second, the treatment causes no observable side effects on the growth of the samples tested.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.1
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• pp.35-46
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• 1998

Structural damage is used to be modeled through reductions in the stiffness of structural elements for the purpose of damage estimation of structural system. In this study, the concept of joint damage is employed for more realistic damage assessment of a steel structure. The joint damage is estimated damage based on the mode shape informations using neural networks, The beam-to-column connection in a steel frame structure is represented by a rotational spring at the fixed end of a beam element. The severity of joint damage is defined as the reduction ratio of the connection stiffness with respect to the value of the intact joint. The concept of the substructural identification is used for the localized damage assessment in a large structure. The feasibility of the proposed method is examined using an example with simulated data. It has been found that the joint damages can be reasonably estimated for the case with the measurements of the mode vectors subjected to noise.