• Title/Summary/Keyword: Urban Dynamics

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CFD Simulation of Changesin NOX Distribution according to an Urban Renewal Project (CFD 모델을 이용한 도시 재정비 사업에 의한 NOX 분포 변화 모의)

  • Kim, Ji-Hyun;Kim, Yeon-Uk;Do, Heon-Seok;Kwak, Kyung-Hwan
    • Journal of Environmental Impact Assessment
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    • v.30 no.3
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    • pp.141-154
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    • 2021
  • In this study, the effect of the restoration of Yaksa stream and the construction of an apartment complex by the urban renewal project in the Yaksa district of Chuncheon on air quality in the surrounding area was evaluated using computational fluid dynamics (CFD) model simulations. In orderto compare the impact of the project, wind and pollutant concentration fields were simulated using topographic data in 2011 and 2017, which stand for the periods before and after the urban renewal project, respectively. In the numerical experiments, the scenarios were set to analyze the effect of the construction of the apartment complex and the effect of stream restoration. Wind direction and wind speed data obtained from the Chuncheon Automated Synoptic Observing System (ASOS) were used as the inflow boundary conditions, and the simulation results were weighted according to the frequencies of the eight-directional inflow wind directions. The changes in wind speed and NOX concentration distribution according to the changes in building and terrain between scenarios were compared. As a result, the concentration of NOX emitted from the surrounding roads increased by the construction of the apartment complex, and the magnitude of the increase was reduced as the result of including the effect of stream restoration. The concentration of NOX decreased around the restored stream, while the concentration increased significantly around the constructed apartment complex. The increase in the concentration of NOX around the apartment complex was more pronounced in the place located in the rear of the wind direction to the apartment complex, and the effect remains up to the height of the building. In conclusion, it was confirmed that the relative arrangement of apartment complex construction and stream restoration in relation to the main wind direction of the target area was one of the major factors in determining the surrounding air quality.

Retrofit strategy issues for structures under earthquake loading using sensitivity-optimization procedures

  • Manolis, G.D.;Panagiotopoulos, C.G.;Paraskevopoulos, E.A.;Karaoulanis, F.E.;Vadaloukas, G.N.;Papachristidis, A.G.
    • Earthquakes and Structures
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    • v.1 no.1
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    • pp.109-127
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    • 2010
  • This work aims at introducing structural sensitivity analysis capabilities into existing commercial finite element software codes for the purpose of mapping retrofit strategies for a broad group of structures including heritage-type buildings. More specifically, the first stage sensitivity analysis is implemented for the standard deterministic environment, followed by stochastic structural sensitivity analysis defined for the probabilistic environment in a subsequent, second phase. It is believed that this new generation of software that will be released by the industrial partner will address the needs of a rapidly developing specialty within the engineering design profession, namely commercial retrofit and rehabilitation activities. In congested urban areas, these activities are carried out in reference to a certain percentage of the contemporary building stock that can no longer be demolished to give room for new construction because of economical, historical or cultural reasons. Furthermore, such analysis tools are becoming essential in reference to a new generation of national codes that spell out in detail how retrofit strategies ought to be implemented. More specifically, our work focuses on identifying the minimum-cost intervention on a given structure undergoing retrofit. Finally, an additional factor that arises in earthquake-prone regions across the world is the random nature of seismic activity that further complicates the task of determining the dynamic overstress that is being induced in the building stock and the additional demands placed on the supporting structural system.

Basic Study for Evaluation on Application of Energy Lining Segment (Energy Lining Segment 적용성 평가를 위한 기초연구)

  • Han, Sang-Hyun;Park, Sisam
    • Journal of the Korean Geosynthetics Society
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    • v.12 no.4
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    • pp.143-147
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    • 2013
  • Geothermal energy is easy to take advantage of renewable energy stored in the earth and the heat exchanger can be collected through a heat exchange piping system. In this study, have been developed a heat exchange pipe loop system which it could be installed in tunnel segmental linings to collect geothermal energy around the tunnel. The heat exchange pipe loop system incorporated in the tunnel segments circulate fluid to transport with heat from the surrounding ground and the heat can be used for heating and cooling of nearby structures or districts. The segmental lining incorporating heat exchange pipe loop system are called as ELS (Energy Lining Segment). There are a number of examples incorporating a heat exchange pipe loop system in a tunnel lining in Europe. In this study, a field case using Energy Lining Segment in Germany and applications in urban area are thoroughly examined. In addition, a CFD (Computational Fluid Dynamics) analysis was carried out to investigate heat flow in Energy Lining Segment.

Estimation of Settling Efficiency in Sedimentation Basin Using Particle Tracking Method (입자추적기법을 이용한 침전지의 효율 평가)

  • Lee, Kil-Seong;Kim, Sang-Hoon
    • Journal of Korea Water Resources Association
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    • v.37 no.4
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    • pp.293-304
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    • 2004
  • Sedimentation basin plays an important role in urban water treatment, and there are many complicated phenomena which need to be understood for efficient design and control of it. Especially, the study on the improvement of settling efficiency is required. In this study, commercial CFD (Computational Fluid Dynamics) program, FLUENT, and particle tracking method were used to simulate the flow in sedimentation basin, and to predict the settling efficiency. Computational domain of real scale was made, and detail factors such as porous wall, and outlet trough were considered instead of being simplified. The simulation results were compared with the experimental data to calibrate the parameters of particle tracking method. Sensitivity analysis showed that the particle diameter had more significant effects on settling efficiency than the particle density. The computation results gave the best agreements with the experimental data, when the value of particle diameter was 26.5 ${\mu}{\textrm}{m}$.

Prediction of Effect on Outside Thermal Environment of Building and Green Space Arrangement by Computational Fluid Dynamic (CFD 시뮬레이션을 이용한 건축물 및 녹지배치가 외부 열환경에 미치는 영향 예측)

  • Kim, Jeong-Ho;Son, Won-Duk;Yoon, Yong-Han
    • Journal of Environmental Science International
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    • v.21 no.1
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    • pp.69-81
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    • 2012
  • This study forecasts changes in thermal environment and microclimate change per new building construction and assignment of green space in urban area using Computational Fluid Dynamics(CFD) simulation. The analysis studies temperature, humidity and wind speed changes in 4 different given conditions that each reflects; 1) new building construction; 2) no new building construction; 3) green spaces; and 4) no green spaces. Daily average wind speed change is studied to be; Case 2(2.3 m/s) > Case 3. The result of daily average temperate change are; Case 3($26.5^{\circ}C$) > Case 4($24.6^{\circ}C$) > Case 2($23.9^{\circ}C$). This result depicts average of $2.5^{\circ}C$ temperature rise post new building construction, and decrease of approximately $1.8^{\circ}C$ when green space is provided. Daily average absolute humidity change is analysed to be; Case 3(15.8 g/kg') > Case 4(14.1 g/kg') > Case 2(13.5 g/kg'). This also reveals that when no green spaces is provided, 2.3 g/kg' of humidity change occurs, and when green space is provided, 0.6 g/kg change occurnd 4(1.8 m/s), which leads to a conclusion that daily average wind velocity is reduced by 0.5 m/s per new building construction in a building complex.

Regional Classification and Analysis for Promoting Area-specific Policy of Deprived Regions: A Case Study of the Growth Promotion Area Policy (지역 맞춤형 낙후지역 정책을 위한 지역 유형구분 및 특성 분석: 성장촉진지역 정책의 사례 연구)

  • Lee, Won-Ho;Abn, Young-Jin
    • Journal of the Korean association of regional geographers
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    • v.17 no.1
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    • pp.96-108
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    • 2011
  • In spite of arduous policy efforts to address the deprived region problem emerged in the rapid industrialization and urbanization processes since the 1960s, it is well acknowledged that there are some policy limitations. In a recent effort to improve the policy for the deprived regions, the national territory is divided into 4 groups such as urban, rural, growth promotion, and special situation areas and various policies for the deprived regions have been consolidated into a policy for the growth promotion areas. The purpose of the study is to classify the already-designated 70 growth promotion areas and examine the differentiated characteristics of different types in order to propose more regionally situated policy approach to the deprived areas. The study shows that the types of the 70 growth promotion areas are much differentiated one another in terms of internal characteristics and dynamics. It is therefore further argued that the policy efforts need to be area-specific in order to address the policy demand for the deprives regions in a more efficient way.

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Analysis of Preference Survey for the Media Facade Cases according to the Sensibility Keywords (감성 어휘에 따른 미디어 파사드 사례의 선호도 조사 분석)

  • Kim, Ju-Yeon
    • Korean Institute of Interior Design Journal
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    • v.22 no.2
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    • pp.58-67
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    • 2013
  • The methods used in this study included investigation of media facades used for landmarks in downtown areas in previous studies, visits to these areas, and recording of media facades. The changes in the colors or the size of buildings were analyzed among the recorded cases and 12 of these cases were selected for further study. The sensibility preference of the media facades was evaluated by sorting the 12 kinds of media facades, and providing them as materials to a group of 60 participants (40 undergraduate and 20 graduate students majoring in architecture and design) consisting of an equal proportion of males and females. This study addressed the following four_stage questions: 1) Five questions of recognition evaluation about media facades and the cognitive evaluation items of emotional vocabulary and color preference in each research case; 2) sensibility preference items regarding the media facade color design; and 3) design evaluation items of the media facades; 4) Video clips and still images were recorded from a middle distance at 7p.m to 11p.m. in central New York, Singapore, Seoul, and Beijing. The participants looked at the changes in colors through the video clips in each case and evaluated their preferences through 23 pairs of emotional vocabulary items using system dynamics. Construction of an emotional vocabulary followed, based on previous studies about media facades and color design. To evaluate the sensibility preference and the perceived representative colors of the media facade, this study suggests new emotional responses that depended on the color emotional vocabulary of light in the LED lighting technical evaluation methodology. A media facade with a moving change of colors, unlike a fixed landscape color design, suggests a new communication method based on architectural factors. New architectural color coordination can be presented for urban landscapes at night. Designs that factor in the pedestrians' emotional vocabulary or preference should take precedence over the use of high luminance and various colors.

Influence of bi-directional seismic pounding on the inelastic demand distribution of three adjacent multi-storey R/C buildings

  • Skrekas, Paschalis;Sextos, Anastasios;Giaralis, Agathoklis
    • Earthquakes and Structures
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    • v.6 no.1
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    • pp.71-87
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    • 2014
  • Interaction between closely-spaced buildings subject to earthquake induced strong ground motions, termed in the literature as "seismic pounding", occurs commonly during major seismic events in contemporary congested urban environments. Seismic pounding is not taken into account by current codes of practice and is rarely considered in practice at the design stage of new buildings constructed "in contact" with existing ones. Thus far, limited research work has been devoted to quantify the influence of slab-to-slab pounding on the inelastic seismic demands at critical locations of structural members in adjacent structures that are not aligned in series. In this respect, this paper considers a typical case study of a "new" reinforced concrete (R/C) EC8-compliant, torsionally sensitive, 7-story corner building constructed within a block, in bi-lateral contact with two existing R/C 5-story structures with same height floors. A non-linear local plasticity numerical model is developed and a series of non-linear time-history analyses is undertaken considering the corner building "in isolation" from the existing ones (no-pounding case), and in combination with the existing ones (pounding case). Numerical results are reported in terms of averages of ratios of peak inelastic rotation demands at all structural elements (beams, columns, shear walls) at each storey. It is shown that seismic pounding reduces on average the inelastic demands of the structural members at the lower floors of the 7-story building. However, the discrepancy in structural response of the entire block due to torsion-induced, bi-directionally seismic pounding is substantial as a result of the complex nonlinear dynamics of the coupled building block system.

Human-Induced Vibrations in Buildings

  • Wesolowsky, Michael J.;Irwin, Peter A.;Galsworthy, Jon K.;Bell, Andrew K.
    • International Journal of High-Rise Buildings
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    • v.1 no.1
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    • pp.15-19
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    • 2012
  • Occupant footfalls are often the most critical source of floor vibration on upper floors of buildings. Floor motions can degrade the performance of imaging equipment, disrupt sensitive research equipment, and cause discomfort for the occupants. It is essential that low-vibration environments be provided for functionality of sensitive spaces on floors above grade. This requires a sufficiently stiff and massive floor structure that effectively resists the forces exerted from user traffic. Over the past 25 years, generic vibration limits have been developed, which provide frequency dependent sensitivities for wide classes of equipment, and are used extensively in lab design for healthcare and research facilities. The same basis for these curves can be used to quantify acceptable limits of vibration for human comfort, depending on the intended occupancy of the space. When available, manufacturer's vibration criteria for sensitive equipment are expressed in units of acceleration, velocity or displacement and can be specified as zero-to-peak, peak-to-peak, or root-mean-square (rms) with varying frequency ranges and resolutions. Several approaches to prediction of floor vibrations are currently applied in practice. Each method is traceable to fundamental structural dynamics, differing only in the level of complexity assumed for the system response, and the required information for use as model inputs. Three commonly used models are described, as well as key features they possess that make them attractive to use for various applications. A case study is presented of a tall building which has fitness areas on two of the upper floors. The analysis predicted that the motions experienced would be within the given criteria, but showed that if the floor had been more flexible, the potential exists for a locked-in resonance response which could have been felt over large portions of the building.

The Comparison of formative Characteristics Clothing in Fashion and Art to Wear.-focused on Art to Wear of Futurism in 1910~1930 (유행의상과 예술의상의 조형적 특성 비교-미래주의 예술의상을 중심으로-)

  • 양취경
    • Journal of the Korean Society of Costume
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    • v.38
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    • pp.51-72
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    • 1998
  • Futurists objected the existent style, that is the conventional fashion, and took part in these disciplines of fashion to make clothes the instruments being able to represent the individuality. Giacomo Balla and fortunato Depero, pain-ters who in 1915 were to work with Diaghilev's company, were the first to see clothing as a dynamic interfaced between th body and the atmosphere, between physical gestures and the urban context, which could be translated into encounters between forms and colours, volumes and architecture. For them, clothing began to exist as an object and an event, something to be removed from a mainly static conception and made mobile, active. The interaction between movement and clothing was based on the relativity of perception : the appearance and disappearance of the body produced points without dimension or duration which served, as Balla wrote in the Futurist Mnaifesto of Men's Clothing to“renew incessantly the enjoyment and impetuous movement of the body”. The historical achievement in the effort for the reformation of Futurist, Art to Wear. First, for Futurist, clothing is removed from a static conception and focused on dynamics. Second, Balla used asymmetry in men's clothing. Moreover he supposed dynamic men's clothes by using optical intersection. Third, the after image of Chronophotograph represented rapidity. This rhythmic expression is the fore-runner in Optical and Kinetic Art of Visual Art. Fourth, Futurist emphasized flexibility in fashion. They aimed to create‘Clothing Machines’whose parts would interact to aceelerate the real and virtual, inner and outer movement of the human being. Fifth, the variety and short life of cutting skills and colors are focused and‘Fast Substance’in fashion is admitted by Futurists. Futurist concern with clothing was not lim-ited its appearance in terms of cut and colour. What important was also the way it appeared and disappeared according to fashion. It was a“fast substance”, able to reflect rapid, sudden changes of social and aesthetic taste. To reach to the aim of internationalization, Gesamtkunstwerk in our Art to Wear, it is extremely meaningful to examine art fashion which is created under the conception of Gesamtkunstwerk production of avang garde artist in the early 20th century and look at formative conscious of truth, goodess and beauty synthetically which they faced on their works of art.

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