• Journal of the Society of Disaster Information
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• v.15 no.3
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• pp.418-426
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• 2019

Purpose: After analyzing the seismic capability of low-rise RC grid structures with insufficient seismic performance, the purpose of the project is to install steel slab hysteretic dampers (SSHD) to improve the seismic performance of beams and columns, and to suggest measures to minimize damage to the structure and human damage when an earthquake occurs. Method: The evaluation of the seismic performance of a structure is reviewed based on the assumption that the seismic performance is identified for the grid-type subway systems that are not designed to be seismic resistant and the installation of an SSHD system, a method that minimizes construction period, if insufficient, is required. Result: After the application and reinforce of structure with SSHD, and the results of eigenvalue analysis are as follows. The natural periodicity of longitudinal direction was 0.55s and that of vertical direction was 0.58s. Conclusion: As results of cyclic load test of structure with SSHD, the shear rigidity of damper is 101%, the energy dissipation rate is 108% and, plastic rotation angle of all column and beam is satisfied for $I_o$ level and therefore it is judged that the reinforce effect is sufficient.

• Korean journal of applied entomology
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• v.58 no.2
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• pp.159-164
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• 2019

The purpose of this study was to investigate whether leaf damage in pear orchards caused by large black chafer beetles can be controlled through net traps and clove oil treatment. In June 2017, we measured large black chafer beetle population density and leaf damage rates in two orchards, located in Boseong and Hampyeong, under three treatments: net, net plus clove oil, and control. In order to evaluate the effect of net position on the adult beetles, nets were placed outside the orchard and along the upper and lower parts of a horizontal trellis. The adult beetle population density was 20.4 to 34.7% lower in the net alone treatment, and 21.1 to 38.1% lower in the combined net and clove oil treatment than in the control. The adult beetle population density was 10.9-14.4 times higher outside the orchard and 5.1 to 9.1 times higher in the upper parts of the horizontal trellis than in the lower parts of the horizontal trellis. Leaf damage under both the net only and net plus clove oil treatments was significantly lower than that in the control at both sites. Therefore, intensive net installation around orchards may be a practical organic alternative to prevent leaf damage caused by large black chafer beetles.

• Journal of The Korean Society For Urban Railway
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• v.6 no.4
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• pp.383-392
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• 2018

This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.1
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• pp.54-67
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• 2021

At present, CPTED projects are showing an effect such as reducing the anxiety of residents from crimes and improving the criminal environment about crimes through crime prevention. However, most of the CPTED programs have been implemented mainly to improve the physical environment without verifying systematically and empirically on the relationship between the program and improving the quality of life of residents and satisfaction level of residents etc. Accordingly, the objective of this study is to grope for a plan to apply CPTED to urban regeneration for improvement in the safety and life quality of residents using AHP and Visualizing The Mental Map. For this, We selected four case areas in Busan and then analyzed the dead zones of CPTED programs by visualizing the mental maps and heat maps of residents for case districts. As a result of evaluating the priority of CPTED program, installation of CCTVs and streetlights for prevention of crimes was found to be the most important elements. Result of analyzing mental map, the existing crime prevention facilities and CPTED programs were found to have resolved most of physical disorder. However, it showed that, for psychological factors which the residents feel such as social disorder, a number of dead zones exist.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.882-889
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• 2021

Purpose: The purpose of this study was to improve fire safety in Gosiwon, a residential space for the low-income class. Method: Problems appearing in the process of fire occurrence and damage were verified once again. In addition, we would like to suggest improvement measures through systematic discussions on blind spots. Results: As a result of examining the risk of cool fire, the causes of fire occurred in various ways. In addition, the possibility of radiant heat due to heat accumulation due to narrow rooms inside the Gosiwon was high. Also, it was found that the possibility of fire spread was high due to clothing and household goods. It was reconfirmed that the poor internal structure of a narrow indoor space had a significant effect on the spread of fire and the scale of damage as it tried to accommodate as many people as possible inside. Conclusion: It is necessary to complete the installation as soon as possible for Gosiwon where the simple sprinkler is not installed. For this, a stronger driving force from the government and local governments is needed. In addition, it will be necessary to discuss how to improve the spatial and structural fire vulnerabilities that appear due to the structural characteristics of the Gosiwon.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.1
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• pp.95-108
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• 2022

The increase in the use time of tunnel users due to the lengthening of the road tunnel may increase the evacuation time in case of fire, resulting in a large number of casualties. In order to reduce the casualties caused by fire, the "Road Tunnel Design Manual, Part 6 Tunnel" and "Road Tunnel Disaster Prevention Facility Installation and Management Guidelines" stipulate that ventilation facilities should be installed along with the extension of the tunnel. The ventilation system design factor considers the wind speed of the external natural wind to be at least 2.5 m/s, and it is applied upward according to the characteristics of the tunnel. As a result of analyzing the five-minute average wind speed data in the Daegwallyeong region for the past 6 years, it was analyzed that 15.8% of the windy days were winds of 10 m/s or more, and the maximum was 20 m/s. Therefore, in this study, when a fire occurs in a tunnel, the pattern of natural wind flowing into the tunnel and the backlayering distance of the tunnel fire smoke according to the maximum wind speed were analyzed. As a result, it was analyzed that a backflow of up to 490 m occurs when a gust of 20 m/s blows.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.135-142
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• 2021

In this work, multi-turn wings and guide plates are installed on recycled aggregate crushing devices to improve existing low recycled aggregate quality. Simulation analysis to evaluate the crushing efficiency of the new device shows enhanced crushing efficiency since the installation of guide plates shreds most of the inputs inside the crushing drum, and the multi-turn wings and guide plates induce rebound and circulation of the aggregate. Through this, the new device was found to be more economical and efficient than the existing recycled aggregate crushing device. Also, the amount of cement paste and mortar attached to the surface of the aggregate was smaller than that of the existing recycled aggregate, and it was found that the mechanical properties and elastic modulus deterioration were reduced. However, the carbonation resistance of concrete was not improved to the level of natural aggregates due to the remaining tiny cement paste and mortar on the surface of the new recycled aggregate. Therefore, it is deemed necessary to further research and experiment such as device improvement or binder development to reduce durability degradation of concrete mixed with new recycled aggregate.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.76-88
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• 2022

Urban parks play the role of providing leisure spaces for people in their everyday life along with serving ecological functions in the city. Although urban parks aim to satisfy the needs of users visiting the park, most urban parks are currently uniformly created and maintained without considering the environmental characteristics based on the needs of users. This study thus analyzed parks that underwent modifications in line with the revised Park Act in 2005. There were 45 parks whose types were legally changed, of which 21 were changed from children's parks to small parks, and 19 were changed to utilize and highlight the themes such as cultural parks and historical parks. Among the parks whose types have changed, the ratio of amenities in cultural and historic parks has increased, while the facility area in small parks has decreased and the green area has increased in its place. As a result of analyzing the changes to the park facility area, it was confirmed that increasing park amenities has a positive effect in pursuing revitalization of use through park maintenance, but has a negative consequence of significantly decreasing green area. It is necessary to reorganize the park type classification system to reflect the park environment and prepare guidelines for a new installation standard by park type to expand the net function of parks in cities and maintain the sustainable ecological environment. Through in-depth discussions on the facilities of park types, it is anticipated that innovative and multilateral research could be conducted to prepare improvement measures tailored to the guidelines of urban park types in years to come.

• Journal of the Korean Society of Floral Art and Design
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• no.44
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• pp.3-31
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• 2021

To verify the types of effects that plants have in our general living conditions, I examined an air quality in living rooms of the three, 129.78m² size, apartments that were with and without plants. and the findings of the study were as addressed below. 1) Experiments showed no statistically significant differences in Case A. However, in Case B and Case C, the standard deviation of PM10, PM2.5 and PM 1.0 verified that each had statistically significant (p<.01) differences. 2) It is believed that the effect of reducing particle matters due to the installation of plants in the indoor space is to vary significantly depending on the indoor environmental conditions, the cleanliness of the room, and the amount of furniture and may also differ depending on the daily dietary cooking method. In addition, it is believed that the planterior will not only reduce indoor fine dust, but also reduce the psychological comfort and eye fatigue of the residents. Nevertheless, supplementary research is needed. 3) In the planterior design for reducing indoor particle matters, various measures were examined. Among them, the vertical wall design method was tested and suggested through empirical experiments. In addition, maintenance methods were proposed depending on the type of indoor plant.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.66-73
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• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.