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A Study on the Recirculation Flow Characteristics with the Change of Shape in a Flue Gas Recirculation Device using Coanda Nozzle (코안다 노즐을 이용한 배기가스 재순환 장치의 형상에 따른 재순환 유동 특성에 관한 연구)

  • Ha, Ji Soo;Shim, Sung Hun;Kim, Dae Yeon
    • Journal of the Korean Institute of Gas
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    • v.23 no.3
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    • pp.1-6
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    • 2019
  • The purpose of the present study is to elucidate flue gas recirculation device for reduction of nitrogen oxides using coanda nozzle without adopting additional power driving fan in a waste incinerator. The characteristics of the exhaust gas recirculation flow rate and the average temperature change at the outlet of the mixed gas were investigated according to the change of air supply nozzle gap and the position of air supply nozzle. When the gap of the air supply nozzle was changed to 3.22, 4.03, and 4.84 mm, the largest recirculation flow ratio, which is the ratio of exhaust gas recirculation flow rate and air supply flow rate, was 2.227 for the case with 3.22 mm and its mean temperature at outlet was $594.8^{\circ}C$. When the position of the air supply nozzle changes to the front position, neck position, and expansion position of the coanda nozzle neck, the recirculation flow ratios at the forward position and the neck position were nearly almost the same value, 1.843, and 1.696 at the expansion position, their mean temperatures were $559.8^{\circ}C$ and $544.3^{\circ}C$, respectively.

A Study on the Original Position of Wibongmun and Joyangru and Signboard Handwriting in the Chuncheon (춘천 위봉문(威鳳門)·조양루(朝陽樓)의 원위치 비정과 현판 글씨 고찰)

  • Lee, Sang-kyun
    • Korean Journal of Heritage: History & Science
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    • v.46 no.2
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    • pp.150-165
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    • 2013
  • This study aims to investigate the original position, the writer of signboard handwriting and the period of Wibongmun and Joyangru in order to restore Wibongmun and Joyangru which have been designated as tangible cultural properties (有形文化財). They also have to be moved in the Gangwon Provincial Office. Wibongmun and Joyangru were established as government offices in chuncheon(春川官衙) and they were used as attached buildings in Chunceon (春川離宮) in 1890. Wibongmun was moved to Gangwon Provincial Office 5 times and Joyangru was moved twice. In order to move them back to the original place, by using the topographic map made by the Japanese Government-General in Korea, we find out Joyangru was located in the exit of Gangwon Provincial Office and greenhouse and we also figure out Wibongmun was located in the garden. While we study historical evidence on handwriting, we also find out the handwriting of Joyangmun was written by Songhaong (松下翁) Jo, Yun-Hyeong (曺允亨). Especially, Joyangru had played a role as a government office and it may be called 'Joyangru' after reconstructing 'Joyangmun' when attached buildings were established. Through this study, we found that the first period and reason of establishing Wibongmun and Joyangru was at least before 1788. Through this study, we can find the period of both and its historic meaning more clearly.

A Study on the Design Improvement of Sign System in Gimpo Urban Railway Station (김포 도시철도역 사인시스템 디자인 개선에 관한 연구)

  • Yang, Keunyoung;Son, Kwang-ho
    • The Journal of the Korea Contents Association
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    • v.21 no.4
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    • pp.785-794
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    • 2021
  • This study investigated the current status of the design and direction of improvement of the sign system of urban railway stations in the Seoul metropolitan area to see how difficult it is for users to use. As a research method, first, a theoretical study on the literature of the urban railway sign system, second, a survey on the current status of the sign design of the Gimpo Goldline in the Seoul metropolitan area, and third, a survey on the actual use of the sign and problems was conducted. As a result of the current status survey, the location sign is in central alignment with the font of the guide sign, and the guidance sign is in front/back alignment according to the location of the entrance and exit. The background of the font is white and the text is dark black to make it look good to the user. On the other hand, guidance sign is written in white color and background color is gray color. Currently, the Gimpo Urban Railway Guidance Sign System is newly produced and installed, but there is a lack of user design and needs design maintenance that can clearly deliver information to users.

A Study on the Improvement of the Disaster Prevention and Control System for Underpasses by Analytic Hierarchy Process (계층분석법을 통한 지하차도 재해 예방 및 제어 시스템 개선 연구)

  • Kim, Phil Do;Kim, Kyoung Soo;Moon, Yoo Mi
    • Journal of the Society of Disaster Information
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    • v.16 no.4
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    • pp.734-746
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    • 2020
  • Purpose: Increase in the size and number of underpasses rises occurrence of disasters such as fire and flooding inundation in underpasses. In the occurrence of disasters, the underpasses are more vulnerable to expose of crucial disasters than the general roads due to they are built underground. Therefore, The purpose of this paper is to derive system improvement items to prevent and control disasters in underpasses. Method: A hierarchical model of disaster impact factors and alternatives was developed based on prior researches and expert advices on disaster analyses and impact factors in the underpasses. The developed model was employed for surveys of pairwise comparison, and rankings of improvement were determined by applying the AHP method. Result: With a consistency of the surveys, results of relative weights of evaluation criteria(traffic accidents, fire, flooding inundation) and alternatives(law, system/planning, maintenance/human factor/environment) shows that improvement of laws and system related to the fire disaster is a top priority to prevent and control disaster of the underpasses. Conclusion: From experts' point of view, strengthening laws and systems related to disater prevention facilities such as water spray facilities, external(ground) exit in relation to fire in underpasses showed that it is an alternative to prevent disasters and minimize damage to underpasses.

Analysis of Truck Platooning Operation Conditions Affecting Traffic Flow (교통류에 영향을 주는 화물차 군집주행 운영 조건 분석)

  • Jung, Harim;Lee, Young-taek;Park, Sangmin;Cho, Hyunbae;Yun, Ilsoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.20 no.4
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    • pp.106-117
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    • 2021
  • In Korea, interest in truck platooning is increasing because most cargo transportation is done by road. Truck platooning is the operation of two or more trucks in a row to form one platoon, which can increase road capacity and improve fuel efficiency. In this study, to analyze the effect of truck platooning on traffic flow, scenarios were created according to traffic conditions and truck platooning operating conditions. In order to understand the effect of the truck platooning operating conditions, correlation analysis was conducted with the average travel speed, the number of lane change disturbance, and the number of disturbance in the entry/exit section. As a result, the number of trucks in the platoon, the spacing of trucks in the platoon, and the spacing between platoons were found to have an effect on the average speed and the number of lane change disturbance In addition, the truck platooning ratio was found to have a strong correlation with the average travel speed and the number of lane change disturbance regardless of the LOS.

Turbine Efficiency Measurement of Pulsating Flow in a Twin Scroll Turbocharger (맥동 유동이 있는 트윈 스크롤 터보과급기의 터빈 효율 측정)

  • Chung, Jin-Eun;Jeon, Se-Hun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.386-391
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    • 2021
  • Turbocharging is becoming a key technology for both diesel and gasoline engines. Regarding gasoline engines, turbocharging can help reduce carbon dioxide (CO2) emissions when used in conjunction with other technologies. This paper presents measurements of the turbine efficiency of pulsating flow in a twin-scroll turbocharger for gasoline engines. A cold gas test bench with a pulse generator was manufactured. The turbine efficiencies were calculated using the measured data of the instantaneous pressure and temperature of the inlet and exit of the turbine. The measurements were carried out at turbine speeds from 60,000 to 100,000 rpm under a pulsating flow of 25.0 Hz and 33.0 Hz. The turbine efficiencies ranged from 0.517 to 0.544. At the pulse frequency, 33.3 Hz, the variations in efficiency were 7.7% and 2.6% at turbine speeds of 60,000 rpm and 100,000 rpm, respectively. The turbine efficiency of the pulsating flow compared to those of steady flow was 7.0% and 3.0% lower at a turbine speed of 60,000 rpm and 100,000 rpm, respectively. The pulsating flow deteriorated the turbine efficiency, but the effects of pulsating flow decreased with increasing turbine speed.

Monitoring Urban Ecological corridors in Gwanggyo New Town Using Camera Trapping (카메라트래핑을 활용한 광교신도시 내 도시형 생태통로 모니터링)

  • Park, Il-Su;Kim, Whee-Moon;Kim, Seoung-Yeal;Park, Chan;Song, Won-Kyong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.24 no.1
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    • pp.69-80
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    • 2021
  • The new town in Korea, developed as a large-scale housing plan, has created urban ecological corridors to provide habitat and movement routes to wildlife and to promote natural ecological flow. This study aimed to investigate the use of wildlife in 10 ecological corridors in Gwanggyo New Town through camera trap technology and confirm effectiveness by identifying environmental factors affecting the use of wildlife's urban ecological corridors. Our researchers installed 20 unmanned sensor cameras at each the entrance and exit of the ecological corridors, and monitored urban wildlife for 10 weeks. According to the monioring results, the main species in Gwanggyo New Town were identified not only raccons, cats, water deer, korean hare and avain but also magpies, dove, eurasian tree sparrow, ring-necked pheasant, and eurasian jay. The number of uses ecological corridors of urban residents was 801(13.49%), as high as that of urban wildlife (1,140, 19.20%), which was judged to have disturbed the use of ecological corridors by wildlife. However, most dominant species of urban wildlife are nocturnal so that, it was judged that they share home range with urban residents at a time interval. In addition, according to the correlation analysis results between the mammal using rate of the urban ecological corridors and environmental factors(ecological corridor-specific length, ecological corridor-specific width, cover degree, shielding degree, connected green area, separation of movement routes, and presence of streetlights), environmental factors were not statistically significant. However, the more the area of green space connected to ecological corridors, the more increasing the mammal using rate of ecological corridor(r=0.71, p<0.05). Therefore, the area of green space connected to the ecological corridors that is associated with rate of wildlife using corridors should be considered as a priority when developing an urban ecological corridors. In the future, this study will extend the observation period of the ecological corridors and continuously accumulate data by adding the number of observation cameras. Furthermore, it is expected that the results of this study can be used as basic data for the standards for urban ecological corridors installation.

An Analysis of Dwelling Environment of Public Retirement(Silver) Housing Based on Post Occupancy Evaluation (거주 후 평가(P.O.E)에 의한 공공실버주택의 거주환경 분석)

  • Bak, Da-Hye;Kim, Young-Hwa;Lee, Sang-Hong
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.12
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    • pp.65-76
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    • 2018
  • Due to the rapid demographic and structural changes, Korea has faced a variety of social issues and quickly entered the aged society since the 2000s. In order deal with this reality, diverse types of welfare policies are emerging in the society as a whole. The government began to supply domestic public silver housing in 2016 to provide against the quickly growing aged society and now, the government is planning to supply approximately 50,000 housing by 2022 for quantitative growth of aged society, by selecting 1st and 2nd designated areas for the project additionally. This public retirement(silver) housing combines 'space' with 'service'. The lower floors are a public silver welfare Facilities and the upper floors are a housing spaces. This type of housing is to deal with requirements of rental housing residents by combining physical space with supporting service. Based on barrier-free design, the complex and unit house have safety handles and alarm bells in the bathroom, undulating washstands, bathroom sliding doors, corridor safety handles, and emergency safety exit lamps in each housing unit so the aged and the disabled can use easily and conveniently. Also, hand rails are installed and stepped pulleys are removed to promote convenience. Currently, the government is planning to increase the supply, focusing on low-income groups, such as beneficiaries of national basic livelihood and the working poor. Recognizing that the public retirement(silver) housing project is at its early stage, this study examined satisfaction, based on evaluations of real residents. This study aimed to obtain more empirical research data and apply them to public retirement(silver) house space analysis. For analysis, this study targeted Wirye public retirement(silver) housing and Magnolia public retirement(silver) housing that are in operation, and literature review, previous research review, and field survey were conducted to examine the present state. Using the questionnaires consisting of four large classification items; Block Layout, Housing Unit, Welfare Facilities, and Barrier-free Design, and sub-details, a survey was conducted to analyze residents' satisfaction. In conclusion, it is anticipated that this study would serve as basic research data about public retirement(silver) housing to increase continuously in future by analyzing public retirement(silver) housing spaces, on the basis of the analyzed data.

A Study on the End of Defects Liability Exit Procedure in Apartment Buildings through Case Studies (사례분석을 통한 공동주택 하자담보책임 종료 절차연구)

  • Kim, Jin-kuk;Bang, Hong-Soon;Choi, Byung-Ju;kim, Ok-Kyue
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.10
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    • pp.25-32
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    • 2018
  • The ending of the warranty under the current Multi-Housing Management Act has a lot of problem as it is very disadvantageous to the business entity and it makes hard for the contractor to finish the repair work. It is almost none for the business entity to get the written confirmation of the expiration of warranty liability from the client even though it sincerely completed their warranty obligation. It is because the client asks for the works other than fair repair arising from the defect in the work, such as the upgrade work for the enhancement of the value of their assets and the repair work which the client should take care before it issues the written confirmation of the expiration of warranty liability to the contractor. "So, though there is the law specifying this matter, the parties are relying on the unnecessary civil agreement. This leads to the big social and economic losses. If there is no agreement made between the client and the contractor, that leads to the legal dispute. This research on cases of 10 apartments shows that the types of works which the apartment residents ask for depend on the characteristics and conditions of the apartments and that they ask for various kinds of compensational works. In addition, it was found that there were many cases in which even the civil agreement is not recognized as the ending of the warranty obligation even if the proper procedure is taken for the ending of warranty by the contractor or business entity. If the collateral is to be offered to the client, the contractor would get more hard because there is the additional cost other than the warranty obligation, thus damaging the legal objective of the laws trying to minimize the damage made to the resident of the apartments. It means that the increase in the unnecessary warranty cost would lead to the increase in the selling price of apartment and the ending of the dispute through the civil procedure would make the Multi-Housing Act ineffective.

Predicting Road Surface Temperature using Solar Radiation Data from SOLWEIG(SOlar and LongWave Environmental Irradiance Geometry-model): Focused on Naebu Expressway in Seoul (태양복사모델(SOLWEIG)의 복사플럭스 자료를 활용한 노면온도 예측: 서울시 내부순환로 대상)

  • AHN, Suk-Hee;KWON, Hyuk-Gi;YANG, Ho-Jin;LEE, Geun-Hee;YI, Chae-Yeon
    • Journal of the Korean Association of Geographic Information Studies
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    • v.23 no.4
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    • pp.156-172
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    • 2020
  • The purpose of this study was to predict road surface temperature using high-resolution solar radiation data. The road surface temperature prediction model (RSTPM) was applied to predict road surface temperature; this model was developed based on the heat-balance method. In addition, using SOLWEIG (SOlar and LongWave Environmental Irradiance Geometry-model), the shadow patterns caused by the terrain effects were analyzed, and high-resolution solar radiation data with 10 m spatial resolution were calculated. To increase the accuracy of the shadow patterns and solar radiation, the day that was modeled had minimal effects from fog, clouds, and precipitation. As a result, shadow areas lasted for a long time at the entrance and exit of a tunnel, and in a high-altitude area. Furthermore, solar radiation clearly decreased in areas affected by shadows, which was reflected in the predicted road surface temperatures. It was confirmed that the road surface temperature should be high at topographically open points and relatively low at higher altitude points. The results of this study could be used to forecast the freezing of sections of road surfaces in winter, and to inform decision making by road managers and drivers.