• Journal of Korean Society for Atmospheric Environment
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• v.23 no.2
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• pp.214-224
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• 2007

A three-dimensional computational fluid dynamics (CFD) model with the renormalization group (RNG) $k-{\varepsilon}$ turbulence model is used to examine the effects of difference in building height on flow and pollutant dispersion in asymmetric street canyons. Three numerical experiments with different street canyons formed by two isolated buildings are performed. In the experiment with equal building height, a portal vortex is formed in the street canyon and a typical recirculation zone is formed behind the downwind building. In the experiment with the downwind building being higher than the upwind building, the ambient flow comes into the street canyon at the front of the downwind building and incoming flow diverges strongly in the street canyon. Hence, pollutants released therein are strongly dispersed through the lateral sides of the street canyon. In the experiment with the upwind building being higher than the downwind building, a large recirculation zone is formed behind the upwind building, which is disturbed by the downwind building. Pollutants are weakly dispersed from the street canyon and the residue concentration ratio is largest among the three experiments. This study shows that the difference in upwind and downwind building height significantly influences flow and pollutant dispersion in and around the street canyon.

• Atmosphere
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• v.24 no.3
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• pp.331-341
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• 2014

In this study, the effects of building-roof cooling on scalar dispersion in three-dimensional street canyons are investigated using a computational fluid dynamics (CFD) model. For this, surface temperature of building roof is systematically changed and non-reactive pollutants are released from street bottom in urban street canyons with the aspect ratio of 1. The characteristics of flow, air temperature, and non-reactive pollutant dispersion in the control experiment are analyzed first. Then, the effects of building-roof cooling are investigated by comparing the results with those in the control experiment. In the control experiment, a portal vortex which is a secondary flow induced by ambient air flow is formed in each street canyon. Averaged air temperature is higher inside the street canyon than in both sides of the street canyon, because warmer air is coming into the street canyon from the roof level. However, air temperature near the street bottom is lower inside the street canyon due to the inflow of cooler air from both sides of the street canyon. As building-roof temperature decreases, wind speed at the roof level increases and portal vortex becomes intensified (that is, downdraft, reverse flow, and updraft becomes stronger). Building-roof cooling contributes to the reduction of average concentration of the non-reactive pollutants and average air temperature in the street canyon. The results imply that building-roof cooling has positive effects on improvement of thermal environment and air quality in urban areas.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.2
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• pp.73-82
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• 2009

The traffic volume of Seoul is extremely high in comparison to other major cities in Korea, and the result has been harmful physical and mental exposure to pollution by Seoulites on a regular basis. The street air pollution is more important than the others, because the air pollution generated by street traffic directly impacts the health of nearby pedestrians. This problem requires urgent attention and resolution. Among the factors creating the air pollution originating from the street, is the configuration of streets, which have emerged as the most significant because it is related to air and pollutant dispersion. Therefore, this study was conducted under the assumption that street form affects the air quality. Study sites were classified by street characteristics, and air quality was analyzed in each class. Then the OSPM (Operational Street Pollution Model) was employed to simulate the relationship between street configuration and air quality of streets within the old city center and new city center in Seoul. After that this study analyzed the correlation between air pollution and the spatial configuration of urban streets (ex. street width, building height, building density, etc.) to determine their contributions to air pollution. The outcome of this study is as follows : First, the result that was derived from the correlation analysis between street configuration and air quality hewed that the air pollution of the street is influenced by the average height of building, width of the roads as well as traffic volume. On the roadside, the concentration level of $NO_2$ is mainly affected by the average height of building and the deviation of building height along the street and CO is affected by street width. The outcome of this study can be used as a basis for more sound urban design policies, and the promotion of desirable street environments for pedestrians.

• Atmosphere
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• v.26 no.3
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• pp.423-433
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• 2016

In this study, performance of a computational fluid dynamics (CFD) model is assessed from analysis on air flow pattern which is observed in the artificial street canyon. Field observations focusing on flows were conducted at an artificial street canyon in Magok region. For the observation of three-dimensional airflow structures, twelve three-dimensional wind anemometers (hereafter, CSAT3) were installed inside the street canyon. The street canyon was composed of two rectangular buildings with 35-m length, 4-m width, and 7-m height. The street width (distance between the buildings) is 7 m, making the street aspect ratio (defined by the ratio of building height to street width) of 1. For the observation of above-building wind, a CSAT3 was installed above the northwest-side building. Southwesterly, westerly and northwesterly were dominant in the street canyon during the observations. Because wind direction is parallel to the street canyon in the southwesterly case, westerly and northwesterly were selected as inflow directions in numerical simulations using a computational fluid dynamics model developed through the collaborative research project between National Institute of Meteorological Sciences and Seoul National University (CFD_NIMR_SNU). The observations showed that a well-structured vortex flow (skimming flow) and an evidence of a small eddy at the corner of the downwind building and ground appeared. The CFD_NIMR_SNU reproduced both the observed flow patterns reasonably well, although wind speeds inside the street canyon were underestimated.

• Korean Institute of Interior Design Journal
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• v.20 no.1
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• pp.208-219
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• 2011

This study is intended to formulate the issues through the status analysis and image evaluation for each street on the basis of colors for the outdoor advertisements for part of street side in the oldest downtown for its construction year. Analysing the business type of the street side, it displays the identity of the fashion business area and the color status shown on the outdoor advertisement did not consider the harmony on the other business type and building improvements that it displays chaotic street views in overall. Status of color for the outdoor advertisement compared and analyzed for each street-side to be analyzed with high color contrast with the building structure and outdoor advertisements than the Street B side where there are many businesses of fashion sundries and fashion clothes to form more complicated street scenery visually for the Street A side. The color combination principle of building structure and outdoor advertisement was shown to be the factor for the contrasting unity and diversity. In order not to stimulate this visual confusion, the colors of outdoor advertisement has to be applied on the basis of the color guideline based on the color combination principle of outdoor advertisement and building structure to have the aesthetic harmony overall. As a result of analysis using the KJ method, the present image of the old downtown area was shown with the adjective vocabularies of "complicated", "out-dated", "chaotic", "disorganized", "dirty", "suffocating", and "unilateral", and its image to strive for would be in a total of 6 adjective vocabularies of "well-arranged", "young", "dynamic", "sophisticated", "personable" and "neat", and it has presented the basic foundation of color guideline of outdoor advertisement fit for its image.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.202-210
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• 2009

This research was undertaken to prove the relationship between street mall activation and architectural plan design. The research methodology was established based on the analysis of data of two existing street malls in Korea (Western Dome & LaFesta) and theoretical studies of outdoor space design. The findings from this study are the following: First, building blocks with segments in every 50m or so are ideal for detailed communication between visitors and building contents. Second, the ratio of width of main corridor and building height should be less than 1 to provide intimate feel and keep visitors' attention concentrated in the facility. Third, store unit should have more storefronts to be exposed more to passers-by and lead more pedestrian traffic. Fourth, shape of store unit would rather be wide and shallow, instead of narrow and deep, to have more exposure to the central corridor. Fifth, the building block of the busiest(most expensive) area that is usually at the main entrance area of street mall should be flexible to fit more smaller units to maximize the profitability. Sixth, the main entrance of store should face the main pedestrian corridor to induce the influx of visitors. Lastly seventh, anchor tenant that has strong name recognition is usually located on basement or higher level to induce pedestrian traffic into the mall, key tenants that are strong and familiar brand names should be located at the corner of building block with spacing to attract visitors, provide even distribution of traffic, and support wayfinding, and local tenant should be located at small units along the central corridor or remainder spaces occurred from building core layout.

• Journal of the Korean Institute of Rural Architecture
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• v.15 no.1
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• pp.39-46
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• 2013

There have been numerous researches on Nak-An village in Jeollanamdo, one of the most representative traditional castle village in Korea. Most of them have dealt with general and physical architectural scale and features separately. Therefore this study aims to understand the compositional characteristics of building layout and exterior space and the relations between street system and dwelling unit of folk houses in Nak-An village. The study examined houses of ordinary people in Nak-An village constructed before the village was not affected by foreign influences. 36 folk houses in Nak-An built from nineteenth century to early twentieth century and believed to have few physical changes from the original floor plans and architectural forms were the subjects to be analyzed. The most popular types in building layout are "Open L"and "Open U". The most typical orientation of main building is Southwest. The favorable entry into the dwelling lot is from the side. The street system in the village consists of main streets of South-North, resulting in dwelling lots with North-South axis most general. This site condition forces the entry into the lot from North main street and the side access to the main building. From these findings, the building layout and the entry into the dwelling lot of folk houses in Nak-An are strongly related with street system and conditions of dwelling lot.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.371-378
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• 2022

The Ryomyong Street project is the only construction project for which the construction cost is known, but its scale cannot be estimated because it is marked in North Korean Won. In this paper, the construction cost per m² of North Korean apartment building construction was calculated based on the construction and assembly amount of the Ryomyong Street project. 160 to 1 was calculated as the ratio of the building construction cost per m² between South and North Korea based on the Ryomyong Street project in Pyongyang and Seoul Housing & Communities Corporation. This ratio can be used to assume the construction size presented in North Korean won as there is no official exchange rate between the two Koreas.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.7
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• pp.63-72
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• 2019

The purpose of this study is to apply the types of urban street pattern and the shape of streets to the master plan of a religious community complexes. The street pattern is a framework of urban structure and to understand the urban structure is helpful to understand the nature of urban streets. By analysing the precedent researches, the types of street patterns are classified as a serial pattern, a branching pattern, a grid pattern and a web pattern. The street patterns are hierarchically composed and classified as a differential development and sequential development. There are boundaries and gates where the street space is differentiated to the more private level. The urban streets continue to the architectural streets such as arcades, deck streets, corridors, lobbies and halls. The purposes and results of the master plan of this religious community complexes are as follows. 1) The school area, housing area and service area are properly separated and connected. They are separated by the building masses and connected by the street space in between. 2) The street pattern of this complexes is a serial pattern where the streets are the center of each functional building groups. The entry square is divided by the symbolic building. The one branch is school street and the other is living street. These streets are combined again to the festival street. 3) The architectural streets are organically related to the urban streets. 4) Each street spaces are of adequate form according to its properties as a place. 5) There are boundaries or gates such as a gab between buildings, posts, arches and deck streets according to the relationship between streets.

• Atmosphere
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• v.25 no.3
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• pp.473-482
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• 2015

In this study, street canyons with a higher downwind building (so called, step-up street canyons) are considered for understanding characteristics of flow and reactive pollutants' dispersion as a basic step to understand the characteristics in wider urban areas. This study used a CFD_NIMR_SNU coupled to a chemistry module just including simple $NO_X-O_3$ photochemical reactions. First, flow characteristics are analyzed in step-up street canyons with four aspect ratios (0.33, 0.47, 0.6, 0.73) defined as ratios of upwind building heights to downwind building height. The CFD_NIMR_SNU reproduced very well the main features (that is, vortices in the street canyons) which appeared in the wind-tunnel experiment. Wind speed within the street canyons became weak as the aspect ratio increased, because volume of flow incoming over the upwind building decreased. For each step-up street canyon, chemistry transport model was integrated up to 3600 s with the time step of 0.5 s. The distribution patterns of $NO_X$ and $O_3$ were largely dependent on the mean flow patterns, however, $NO_X$ and $O_3$ concentrations were partly affected by photochemical reactions. $O_3$ concentration near the upwind lower region of the street canyons was much lower than background concentration, because there was much reduction in $O_3$ concentration due to NO titration there. Total amount of $NO_X$ in the street canyons increased with the aspect ratio, resulting from the decrease of mean wind intensity.