• Title/Summary/Keyword: HEED

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Study on the optimal design of floor exhaust system using computational fluid dynamics for subway platform (수치해석을 활용한 승강장 바닥배기 시스템 최적화 연구)

  • Namgung, Hyeong-Gyu;Park, Sechan;Kim, Minhae;Kim, Soo-Yeon;Kwon, Soon-Bark
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.2
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    • pp.443-449
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    • 2017
  • The imbalance of air supply and the exhaust on subway platforms has led to the installation of platform screen doors in underground subway stations. This imbalance causes the accumulation of pollutants on the platform and loss of comfort due to the lack of ventilation. In this study, a floor exhaust system was optimized using computational fluid dynamics (CFD) and an optimization program. The optimized floor exhaust system was manufactured and tested experimentally to evaluate the particle collection efficiency. CFX 17.0 and HEEDS were used to analyze the flow field and optimize the principal dimensions of the exhaust system. As a result of the three-step optimization, the optimized floor exhaust system had a total height of 1.78 m, pressure drop of 430 Pa, and particle collection capability of 61%. A fine dust particle collection experiment was conducted using a floor exhaust system that was manufactured at full scale based on the optimized design. The experiment indicated about 65% particle collection efficiency. Therefore, the optimized design can be applied to subway platforms to draw in exhaust air and remove particulate matter at the same time.

A Study on Environmental Impact Assessment Guidelines for Marine Environmentsin Construction Projects of Offshore Waste Disposal Landfills (해상최종처리장 건설사업의 해양환경 환경영향평가 가이드라인 개발 연구)

  • Lee, Haemi;Son, Minho;Kang, Taesoon;Maeng, Junho
    • Journal of Environmental Impact Assessment
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    • v.28 no.3
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    • pp.312-331
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    • 2019
  • An offshore waste disposal facility refers to a landfill site for final landfilling of stabilized inorganic solid waste such as land and marine waste incineration materials, and the aim of such a facility is to solve the problem of insufficient waste disposal space on land and create and develop environmentally friendly marine spaces. The purpose of this study is to prepare guidelines for the construction of offshore waste disposal facilities, which reflect the need and importance of paying sufficient heed to environmental considerations from the initial stage of the project, in order to investigate, predict, and assess how such guidelines will affect the marine environment in relation to the construction of offshore waste disposal facilities, with the goal of minimizing the impact on and damage to the environment. For the purpose of this research, guidelines focusing on the construction of offshore waste disposal facilities were derived through an analysis of domestic cases and similar foreign cases and an assessment of their level of compliance with existing EIA guidelines through the operation of a discussion forum. In order to review the EIA report on similar cases in Korea, 17 EIA documents (2005~2016) for dredged soil dumping areas and ash ponds of thermal power plants were analyzed to investigate the status of marine organisms, marine physics, marine water quality, and marine sediment and to understand what types of problems can occur and what improvement measures can be taken. The purpose of these guidelines were to minimize damage to the marine environment by promoting EIA protocols in accordance with scientific and systematic procedures, to reduce the consultation period related to projects, to resolve social conflicts, and to reduce economic costs.

A Study on the Optimization of Main Dimensions of a Ship by Design Search Techniques based on the AI (AI 기반 설계 탐색 기법을 통한 선박의 주요 치수 최적화)

  • Dong-Woo Park;Inseob Kim
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.7
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    • pp.1231-1237
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    • 2022
  • In the present study, the optimization of the main particulars of a ship using AI-based design search techniques was investigated. For the design search techniques, the SHERPA algorithm by HEEDS was applied, and CFD analysis using STAR-CCM+ was applied for the calculation of resistance performance. Main particulars were automatically transformed by modifying the main particulars of the ship at the stage of preprocessing using JAVA script and Python. Small catamaran was chosen for the present study, and the main dimensions of the length, breadth, draft of demi-hull, and distance between demi-hulls were considered as design variables. Total resistance was considered as an objective function, and the range of displaced volume considering the arrangement of the outfitting system was chosen as the constraint. As a result, the changes in the individual design variables were within ±5%, and the total resistance of the optimized hull form was decreased by 11% compared with that of the existing hull form. Throughout the present study, the resistance performance of small catamaran could be improved by the optimization of the main dimensions without direct modification of the hull shape. In addition, the application of optimization using design search techniques is expected for the improvement in the resistance performance of a ship.

Effects of Product Number and Brand Breadth on the Evaluations of an Extended Product

  • Yeu, Minsun;Yuk, Hyeyeon;Kim, Boha;Yoo, Jung-Hyun;Cho, Seong Wan;Yeo, Junsang;Park, Chan Su
    • Asia Marketing Journal
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    • v.15 no.3
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    • pp.97-115
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    • 2013
  • This paper was motivated by two gaps in the extant literature on brand portfolio planning. First, research has shown that, as the number of products connected to a brand increases, the extended product receives more favorable evaluations. However, this result was obtained by comparing two brands with different number of products while controlling the brands' breadths. Hence one may question if the above result would hold when the brand is narrow as well as broad. Second, the literature has investigated the effect of brand breadth on the perceived fit and evaluations of an extended product within a relatively limited range ("narrow vs. broad") and not considered the case of a "very broad" brand. To address these gaps, we propose two hypotheses: 1) the effects of the number of products associated with a brand on the perceived fit and evaluations of a moderately far brand extension are moderated by the brand's breadth (H1); and 2) the relationship between a brand's breadth and a moderately far extension's perceived fit and evaluations looks like an inverse-U shape (H2). Study 1 was conducted to test H1. Study 1 employed a 2 × 2 within-subjects design in which the first factor was the number of products (small (2) or large (5)), and the second factor was brand breadth (narrow or broad). We measured brand breadth as the perceived similarity among products associated with a brand. Participants provided the perceived fit and evaluations of an extended product. Study 2 was conducted to test H2 as well as to replicate Study 1 in a more general setting and with different products. It employed a 2 × 3 within-subjects design, in which the first factor was the number of products (small (2) or large (5)), and the second factor was brand breadth (narrow, broad, or very broad). The results from two experiments support both hypotheses. This paper contributes to the literature on brand extensions in two ways. First, it broadens our understanding of the effects of product number and brand breadth on extended product evaluations by considering the two factors jointly. Second, we believe this study to be the first to present evidence that brand breadth can exert an inverted U-shape effect on the perceived fit and evaluations of an extended product. The results also offer implications for marketers. First, marketers should heed the finding that adding similar products to a narrow brand does not help the brand's extension launch. Second, the finding that the relationship between brand breadth and extended product evaluations might not be linear provides practical implications. While a narrow brand should not keep launching close extensions, nor should a broad brand continue producing far extensions to broaden its breadth. A firm with a broad corporate or family brand might want to consider introducing a new brand instead of adding dissimilar products under the brand umbrella.

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The status of care satisfactions of the disabled persons with community-based rehabilitation plan (장애인의 치료만족도에 따른 지역사회중심재활에 관한 연구)

  • Lee In-Hak;Park Rae-Joon;Kim Mi-Ran
    • The Journal of Korean Physical Therapy
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    • v.10 no.2
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    • pp.13-32
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    • 1998
  • A questionaire was conducted to obtain ran satisfactions in information of the 325 disabled persons among the total 9,314 handicapped people in Taejon area, and was surveyed during the period of June 1 to August 31, 1997. The results are as follows: 1. Among the studied disabled persons, $54.5\%$ of male, and $45.5\%$ of female. 2. Before disabled in occupation, $32.0\%$ of out of work group were high, $6.5\%$ of farm, student group were low. Before disabled in occupation by gender, male group is $29.9\%$ of out of work group were high, $0.6\%$ of housework group were low. female group is$34.5\%$ of out of work group were high, $4.7\%$ of student group were low(P<0.001). 3. After disabled in occupation, $75.1\%$ of out of work group wert high, $10.8\%$ of in working group were low. After disabled in occupation by gender, male group is $87.6\%$ of out of work group were high, $1.7\%$ of housework group were low. female group is $60.1\%$ of out of work group were hgh, $10.8\%$ of in working group were low(P<0.001). 4. Medical security status, $64.9\%$ of medical aid group wore high, $35.1\%$ of medical insurance group were low. Medical security status by gender, male group is $71.2\%$ of medical aid group were high, $28.8\%$ of medical insurance group were Iew. female group is $57.4\%$ of medical aid group wan high, $42.6\%$ of medical insurance were low(P<0.01). 5. Disabled record status, $68.6\%$ of record group were high, $31.4\%$ of non group were low. Disabled record status by gender, male group is $78.5\%$ of record group were high, $21.5\%$ of non record group were low. female group is $56.6\%$ of record group were high, $43.4%$ of non record group were low(P<0.001). 6. Disabled duration status, $42.2\%$ of loss than 9 year group were high, $10.2\%\;of\;20-29,\;30-39$ year group were low. Disabled duration status by gender,'male group is $44.6\%$ of less than 9 year group were high, $6.2\%$ of 20-29 year group wert low. female group is $39.2\%$ of less than 9 year were high, $39.2\%$ of 30-39 year group were low (P<0.05). 7. Cause of disabled status, $26.5\%$ of other group, $23.7\%$ of congenital group were high. $9.2\%$ of unknown group, $6.8\%$ of industry accident, $2.5\%$ of drug poisoning group were low. Cause of disabled status by gender, male group is $27.7\%$ of other group, $23.7\%$ of congenital group were high, $2.3\%$ drug poisoning group were low. female group is $25.0\%$ of other group, $20.9\%$ of congenital group were high, $2.5\%$ of drug poisoning group were low (P<0.001). 8. Disabled type status, $19.4\%$ of double disabled group were high, $2.2\%$ of muscle paralysis group were low. Disabled type status by gender, male group is $22.0\%$ of double disabled group were high, $2.3\%$ of muscle paralysis group were low. female group is $23.3\%$ of rheumatism group were high, $0.7\%$ of amputation group were low(P<0.001). 9. Smoking status, $73.2\%$ of non smoking group were high, $26.8\%$ of smoking group were low. Smoking status by gender, male group is $59.9\%$ of double non smoking group were high, $40.1\%$ of Smoking group were low, female group is $89.2\%$ of non smoking group were high, $10.8\%$ of smoking group were low(P<0.001). 10. Drinking status, $80.0\%$ of non drinking group were high, $20.0\%$ of drinking group were low. Drinking status by gender, male group is $72.3\%$ of non drinking group were high, $27.7\%$ of drinking group were low. female group is $89.2\%$ of non drinking group were high, $10.8\%$ of drinking group were low(P<0.001). 11. Stress level status, $52.9\%$ of high stress group were high, $1.8\%$ of very severe stress group were low. Stress level status by gender, male group is $50.8\%$ of high stress group were high, $2.3\%$ of very severe stress group were low. female group is $55.4\%$of high stress group were high, $1.4\%$ of very severe stress group were low. 12. Heed status, $28.0\%$ of economic support were high, $4.6\%$ of speech therapy, brace group were low. Need status by Sender, male group is $2i2\%$ of economic support group were high, $4.5\%$ of bracegroup were low. female group is$27.7\%$ of economic support group were high, $3.4\%$ of speech therapy group were low. 13. Care satisfaction comparision, 3.09, 0.55 point of IBR, 4.01, 0.45 point of CHR(P<0.001). 14. The variables which had positive correlation with IBR were gender(r=0.1406, P<0.01), age(r=0.1872, p<0.001), economic level(r=0.1246, P<0.05), disabled record(r=0.1137, P<0.05), education level(r=-0.1122. p<0.05). 15. The variables which had positive : correlation with CBR were gender(r=0.1613, P<0.01), age(r=0.2255, P<0.001). list of family(r=0.12i3, P<0.01), disabled record(r=0.1273, P<0.05). education level(r=-0.1294, P<0.01).

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