• Journal of the Korean Institute of Landscape Architecture
• /
• v.52 no.4
• /
• pp.45-55
• /
• 2024

This study aims to distinguish between utilitarian walking and leisure walking activities and analyze the correlation between these types of walking and the walking environment. To measure the walking environment, we utilized Google Street View (GSV) and employed semantic segmentation deep learning techniques to quantitatively assess urban walking environment elements as perceived by pedestrians. A survey was conducted to measure utilitarian walking, leisure walking, and perceived walking environment satisfaction, collecting valid responses from 192 participants. Using the survey data, we visualized utilitarian walking, leisure walking, and perceived walking environment satisfaction, and analyzed the correlation between these variables and the walkability scores. The results indicated that leisure walking had a significant positive correlation with walkability (Pearson's r = 0.121, p-value = 0.012), while there was no significant correlation between utilitarian walking and walkability (Pearson's r = 0.093, p-value = 0.055). These findings suggest that people prioritize mobility efficiency over the walking environment for utilitarian walking, whereas the quality of the walking environment significantly influences the frequency of leisure walking. Based on these results, the study proposes specific strategies to improve the walking environment around residential areas to promote leisure walking. These strategies include creating vertical gardens or various forms of three-dimensional gardens on narrow walkways and improving sidewalk design. The findings of this study can contribute to promoting leisure walking by creating walk-friendly environments, ultimately enhancing urban sustainability and the quality of life for residents.

• Land and Housing Review
• /
• v.14 no.4
• /
• pp.77-93
• /
• 2023

The COVID-19 pandemic has brought about significant social changes through government prevention and control measures, changes in people's risk perceptions, and lifestyle changes. In response, urban inhabitants changed their behaviors significantly, including their preferences for transportation modes and urban spaces in response to government quarantine policies and concerns over the potential risk of infection in urban spaces. These changes may have long-lasting effects on urban spaces beyond the COVID-19 pandemic or they may evolve and develop new forms. Therefore, this study aims to explore the potential for urban spaces to adapt to the present and future pandemics by examining changes in urban residents' preferences in travel modes and urban space use due to the COVID-19 pandemic. This study found that overall preferences for travel modes and urban spaces significantly differ between the pre-pandemic, pandemic, and post-pandemic periods. During the pandemic, preferences for travel modes and urban spaces has decreased, except for privately owned vehicles and green spaces, which are perceived to be safe from transmission, show more favorable than others. Post-pandemic preferences for travel modes and urban spaces are less favorable than pre-pandemic with urban spaces being five times less favorable than transportation. Although green spaces and medical facilities that were positively perceived during the pandemic are expected to return to the pre-pandemic preference level, other factors of urban spaces are facing a new-normal. The findings suggest that the COVID-19 pandemic has had a significant impact on urban residents' preferences for travel modes and urban space use. Understanding these changes is crucial for developing strategies to adapt to present and future pandemics and improve urban resilience.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.292-292
• /
• 2016

Transition metal dichalcogenides (TMDs) with a two-dimensional layered structure have been considered highly promising materials for next-generation flexible, wearable, stretchable and transparent devices due to their unique physical, electrical and optical properties. Recent studies on TMD devices have focused on developing a suitable doping technique because precise control of the threshold voltage ($V_{TH}$) and the number of tightly-bound trions are required to achieve high performance electronic and optoelectronic devices, respectively. In particular, it is critical to develop an ultra-low level doping technique for the proper design and optimization of TMD-based devices because high level doping (about $10^{12}cm^{-2}$) causes TMD to act as a near-metallic layer. However, it is difficult to apply an ion implantation technique to TMD materials due to crystal damage that occurs during the implantation process. Although safe doping techniques have recently been developed, most of the previous TMD doping techniques presented very high doping levels of ${\sim}10^{12}cm^{-2}$. Recently, low-level n- and p-doping of TMD materials was achieved using cesium carbonate ($Cs_2CO_3$), octadecyltrichlorosilane (OTS), and M-DNA, but further studies are needed to reduce the doping level down to an intrinsic level. Here, we propose a novel DNA-based doping method on $MoS_2$ and $WSe_2$ films, which enables ultra-low n- and p-doping control and allows for proper adjustments in device performance. This is achieved by selecting and/or combining different types of divalent metal and trivalent lanthanide (Ln) ions on DNA nanostructures. The available n-doping range (${\Delta}n$) on the $MoS_2$ by Ln-DNA (DNA functionalized by trivalent Ln ions) is between $6{\times}10^9cm^{-2}$ and $2.6{\times}10^{10}cm^{-2}$, which is even lower than that provided by pristine DNA (${\sim}6.4{\times}10^{10}cm^{-2}$). The p-doping change (${\Delta}p$) on $WSe_2$ by Ln-DNA is adjusted between $-1.0{\times}10^{10}cm^{-2}$ and $-2.4{\times}10^{10}cm^{-2}$. In the case of Co-DNA (DNA functionalized by both divalent metal and trivalent Ln ions) doping where $Eu^{3+}$ or $Gd^{3+}$ ions were incorporated, a light p-doping phenomenon is observed on $MoS_2$ and $WSe_2$ (respectively, negative ${\Delta}n$ below $-9{\times}10^9cm^{-2}$ and positive ${\Delta}p$ above $1.4{\times}10^{10}cm^{-2}$) because the added $Cu^{2+}$ ions probably reduce the strength of negative charges in Ln-DNA. However, a light n-doping phenomenon (positive ${\Delta}n$ above $10^{10}cm^{-2}$ and negative ${\Delta}p$ below $-1.1{\times}10^{10}cm^{-2}$) occurs in the TMD devices doped by Co-DNA with $Tb^{3+}$ or $Er^{3+}$ ions. A significant (factor of ~5) increase in field-effect mobility is also observed on the $MoS_2$ and $WSe_2$ devices, which are, respectively, doped by $Tb^{3+}$-based Co-DNA (n-doping) and $Gd^{3+}$-based Co-DNA (p-doping), due to the reduction of effective electron and hole barrier heights after the doping. In terms of optoelectronic device performance (photoresponsivity and detectivity), the $Tb^{3+}$ or $Er^{3+}$-Co-DNA (n-doping) and the $Eu^{3+}$ or $Gd^{3+}$-Co-DNA (p-doping) improve the $MoS_2$ and $WSe_2$ photodetectors, respectively.

• Journal of the Korean Institute of Gas
• /
• v.22 no.5
• /
• pp.53-61
• /
• 2018

Low-salinity water based polymerflooding (LSPF) is one of promising enhanced oil recovery (EOR) method that has the synergetic effect of combining polymer injection method and low-salinity water injection method. In order to maximize EOR efficiency, it is essential to design low-salinity water appropriately considering the properties of polymer. In this aspect, the main purpose of this study is to investigate the effect of pH and $SO_4{^{2-}}$ ion which one of PDI (Potential Determining Ion) on oil production when applying LSPF to carbonate oil reservoir. First, the stability and adsorption of polymer molecule were analyzed in different pH of injection water and $SO_4{^{2-}}$ concentration in injection water. As a result, regardless of pH and $SO_4{^{2-}}$ concentration, when $SO_4{^{2-}}$ ion was contained in injection water, the stability of polymer solution was obtained. However, from the result of polymer retention analysis, in neutral state of injection water, since $SO_4{^{2-}}$ interfered the adsorption of polymer, the adsorption thickness of polymer was thinner as $SO_4{^{2-}}$ concentration was higher. On the other hand, when injection water was acidic as pH 4, the amount of polymer adsorption increased with the injection of polymer solution, so the mobility of polymer solution was greatly lowered. From the results of wettability alteration due to low-salinity water effect, in the case of neutral injection water injected, as $SO_4{^{2-}}$ concentration was increased, more oil which attached on rock surface was detached, altering wettability from oil-wet to water-wet. On the other hand, in acidic condition, due to complex effect of rock dissolution and polymer adsorption, wettability of the entire core system was less altered relatively to neutral condition. Therefore, it was evaluated that better EOR efficiency was obtained when injecting low-salinity water based polymer solution containing high concentration of $SO_4{^{2-}}$ with neutral condition, enhancing the oil production up to 12.3% compared to low-salinity water injection method.

• Journal of the Korean housing association
• /
• v.18 no.5
• /
• pp.65-72
• /
• 2007

What is the meaning of home to older people? How much is home significant for older people? How do they express self-identity through decorating their own homes? These are the new subjects that scholars in the West are involved in lately in terms of micro-perspective (George, 1998; Kellett, Gilroy & Jason, 2005; Gilroy & Kellett, 2006). It is evident that home has more significant meaning to older people than other age groups, since the older are more likely to spend greater time within the home through lower income, lessening mobility or loss of companions (Gilroy, 2005). Also the older tend to cling to their homes and attach to possessions than the younger. Older people's possessions are the things that memories of their lives were absorbed. Therefore, possession display can role as a mean of showing their past lives and memories. Gilroy and her colleagues (2005, 2006) found that there was a certain pattern of possession display in English older people's households, and that older people would like to express self-identity through decorating their own homes with their precious possessions. Then, isn't it interesting to find out if there is any pattern of possession display or decoration items in Korean older people's households as well? Thus, the aim of this study is to describe pattern of possession display as a mean of expressing self-identity in Korean older people's households. Interview with older people was used to find out the way and reason of display possessions. Observation method including taking photos and hand-drawings was also added in order to demonstrate detail condition of display items in the house. Possessions display and furniture arrangement in the living room and bedroom were investigated to find out a certain pattern of display and meaning. Research objects were healthy older people aged over 60, who are living independently from their adult children, and who can manage housekeeping by themselves. 32 households were investigated in the area of Seoul, Kyunggi, Chungchungnam, and Kangwon provinces. The findings demonstrate that most precious possession for Korean older people is photo of themselves; especially one taken in their younger age. The reason of it is because the photo reminds them of their heydays when they were vital. Photo of the most beloved one is displayed more frequently in the bedroom than in the living room indicating consistence with English case. As symmetrical display pattern was dominant in case of English older people's households, no dominant display pattern is found in Korean case. Korean older people also cling to their homes and possessions and want to keep their dwelling space as large as what they use now. It is notable that even after they become older and frail, they want sufficient space to display possessions as a mean of self-identity expression. Attachment to possessions and decoration can give older people significant meaning of identity, and it is the reason why architects or interior designers have to meet older people's needs. It needs consideration that residents are allowed to bring their old furniture and precious possessions when they move in elderly housing unit in order to minimize environmental shock, as well as feeling at home. This subject could suggest a clue to designers or architects who have to meet residents' needs in space design of elderly housing or facilities in the future. Psychological well-being of older people can be met by making them feel at home wherever they live. They need space where they can express their own identity and personality even in case when they have to live in a limited small space like elderly housing unit or nursing home.

• (The)Study of the Eastern Classic
• /
• no.50
• /
• pp.295-318
• /
• 2013

The purpose of this study was to define the 'caligraphy as a modern concept of art. For this purpose, it was necessary to exclude the elements betraying 'the caligraphy as a pure art' in reference to 'autonomy' as an indicator of modernity in order to reflect on the current topology of the caligraphy in our age. Checking the current conditions facing the caligraphy from the pre-modern, modern and post-modern perspectives will clarify the current topology of the caligraphy and further exploring 'the caligraphy as a post-modern art concept. To this end, this study defines the caligraphy 'as a pure formative art' and thereby discusses it in terms of nature and form. In terms of nature, the caligraphy should be subsumed into a spacial art, but it has a nature of a temporal art created and appreciated over time. Hence, among the spacial arts, the painting is most similar to the caligraphy, while among the temporal arts, the caligraphy is most similar to such rhythmic (of high mobility) or performing arts as music and dance. Merely, the painting does not reveal the flow of time on the canvas, while music and dance leave no residual in terms of audibility and visuality. All in all, the caligraphy is sort of 'temporal-spacial art' like dance in that the visible letters express the artist's sense of life on the plane over time like music. In terms of form, this study compares the caligraphy with engraving, wood print and character design to define the caligraphy as a pure art concept. The caligraphy as a modern art concept, namely, the autonomy of the caligraphy is associated with legibility and meaning in addition to the question whether it is an applied or a pure art. The legibility and meaning of the characters are not only the essential elements of the caligraphy but also are the factors limiting its autonomy, which must be a paradox. All in all, the legibility and meaning of the characters must be the key criteria for determining the caligraphy as a practical art or literary art or as a pure figurative art. In this context, this study discusses the caligraphy as a pure art by comparing it with the spatial art 'painting' and the temporal art 'music.' It might be impossible to define the caligraphy or a genre of art as an autonomous art of self-perfection and categorical identity. Moreover, any attempt to define the caligraphy would fail to interpret the caligraphy appropriately. Merely, we are obliged to position the caligraphy in the process of localizing 'their modernity' and thereby, discuss how to respond to their scheme.