• The Journal of Asian Finance, Economics and Business
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• v.7 no.9
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• pp.135-145
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• 2020

This paper provides the practical application of a linear shrinkage framework on Vietnam stock market. The cumulative data points observed in this analysis are 468 weeks from January 2011 to December 2019. All the companies listed on Ho Chi Minh City Stock Exchange (HOSE), except the companies under two years period from Initial Public Offering (IPO), are considered. The cumulative number of stocks picked is therefore 350 companies. The VNINDEX, which is the Vietnam Stock Index, is used as a reference index for shrinking to a single-index model. The empirical results show that the shrinkage of covariance matrix for portfolio optimization gives the promising results for the investors on Vietnam stock market. The shrinkage method helps the investors to produce the optimal portfolio in the sense of having higher profit with lower levels of risk compared to the portfolio of the traditional SCM method. Moreover, the portfolio turnover of shrinkage method is always kept at low magnitudes, and this makes the shrinkage portfolios save much transaction costs and reduce the liquidity risks in the trading process. In addition, the ability of shrinkage method in making profit is once again confirmed by the Alpha coefficient that achieves a high positive value.

• Journal of the Korean Regional Science Association
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• v.35 no.4
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• pp.33-45
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• 2019

Due to the global low growth trend, urban shrinkage is a major issue of urban policy in major industrialized countries. According to the research results of the KRIHS(Korea Research Institute for Human Settlements, 2016), 23 out of 77 cities in Korea were diagnosed as continuous or temporary shrinking cities. However, the criterion for diagnosing shrinking cities remain on the simple demographic side, and the spatial shrinkage pattern of the city is not considered. Therefore, this study diagnosed urban shrinkage phenomenon considering the characteristics of Yeong-ju, a poly-centric city, by using the population gradient curve, which is one of the urban spatial structure analysis methods. As a result of the diagnosis, Yeong-ju turned out to be a shrinking city with the population density and the slope of population density increasing. In the case of area of Dong, a sprawl phenomenon in which the population density of the CBD and the slope of the population density were decreased was shown. And in the case of Punggi-eup, a simple shrinkage phenomenon in which only the population density of the CBD was decreased was shown. The results show that even within a city, the pattern of spatial change can be different for each centers. In the case of a city with a poly-centric structure, the implications for the individual diagnosis of not only the entire city but also the detailed area were drawn.

• Journal of Cadastre & Land InformatiX
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• v.52 no.2
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• pp.35-51
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• 2022

This study investigates how much building area among total building area concentrates on urban region in a local government region and then, I applies 'The Index of Building Concentration in Urban Area' for the first time in a study. The finding shows that Cities' Index is higher than counties', and also shows that a lower index is associated with a higher rate of older adult population, and is also associated with higher general budget expenditure by the local government based on the index of Building Concentration in Urban Area in Gyeongbuk Province. This study provides evidence that the Index of Building Concentration in Urban Area can be utilized in measuring shrinkage level, effectiveness of municipal finance, and in establishing shrinkage city/county planning by basic data.

• Clinics in Shoulder and Elbow
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• v.7 no.2
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• pp.76-82
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• 2004

Purpose: In the traumatic anterior shoulder instability, the laxity of joint capsule and ligament is frequently demonstrated. Although a arthroscopic procedure to address anterior instability with joint capsular redundancy have generally provided good results, its recurrence rate is higher than open procedure. By reducing the capsular redundancy, thermal shrinkage is likely to improve the outcome of arthroscopic anterior stabilization. The objective of this study was to evaluate additional thermal capsular shrinkage as a treatment of joint capsular redundancy in anterior shoulder instability. Materials and Methods: From March 1999 to June 2000, 25 shoulders of 23 patients of recurrent anterior shoulder dislocation underwent arthroscopic Bankart repair with shrinkage procedure. The mean follow up was 29 months and average age at the time of operation was 26 years. Of these patients, 20 were male and 3 were female who had been experienced the average 8 times of dislocation before operation. Thermal shrinkage alone without Bankart repair was performed in two cases who did not have Bankart lesion. The clinical result was evaluated in according to Modified Rowe Score. Results: The Modified Rowe Score was improved from preoperative 35 points to postoperative 88 points. None of cases showed recurrence of dislocation. But, in two cases, temporary sensory hypesthesia of the axillary nerve was developed and in two cases of postoperative stiffness, arthroscopic capsular release and brisement were performed. Conclusion: Additional capsular shrinkage in arthroscopic technique to address recurrent anterior shoulder instability could treat effectively the capsular redundancy.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.135-144
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• 2022

This paper aimed to analyze the type of urban shrinkage over the past 20 years for four case cities designated as abandoned mining area promotion zones and present the direction of future urban spatial policies through the analysis of shrinking status. According to the analysis of urban shrinkage in the past 20 years, all of the case cities were analyzed as fixed-type shrinking cities, showing a population decrease of more than 30% over the past 40 years compared to the peak population. Despite the decrease in population, the designated area of urbanization and non-urban areas is increasing every year, and the development permit and construction permit in non-urban areas are also increasing, requiring efficient management and operation of urban space. It is necessary to study military-level cities in the high-risk phase of extinction in the future, and to develop various indicators for segmentation of urban shrinkage types and analysis of status by type.

• Composites Research
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• v.14 no.6
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• pp.47-58
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• 2001

This paper describes applications of cure monitoring techniques by using embedded fiber optic strain sensors, which are extrinsic Fabry-Perot interoferometric (EFPI) and/or fiber Bra99 grating (FBG) sensors, to three kinds of molding methods of autoclave, FW and RTM molding methods. In these applications, internal strain of high-temperature curing resin was monitored by EFPI sensors. From theme experimental results, it was shown that strain caused by thermal shrink at cooling stage could be measured well. In addition, several specific matters to these molding methods were considered. As thor an autoclave molding of unidirectional FRP laminates, it was confirmed that off-axis strain of unidirectional FRP could be monitored by EFPI sensors. As for FW molding using room-temperature (RT) cured resin, it was found that the strain outputs from EFPI sensors represented curing shrinkage as well as thermal strain and the convergence meant finish of cure reaction. It was also shown that this curing shrinkage should be evaluated with consideration on logarithmic change in stiffness of matrix resin. As for a RTM melding, both EFPI and FBC sensors were employed to measure strain. The results showed that FBG sensors hale also good potential for strain monitoring at cooling stage, while the non-uniform thermal residual strain of textile affected the FBG spectrum after molding. This study has proven that embedded fiber optic strain sensors hale practical ability of cure monitoring of FRP. However, development of automatic installation methods of sensors remains as a problem to be solved for applications to practical products.

• Journal of the Korean Regional Science Association
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• v.40 no.2
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• pp.91-106
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• 2024

Around the world, many countries experiencing the issue of shrinking cities are continually expanding high-speed rail networks to enhance regional accessibility and address imbalances. This study analyzed the effects of high-speed train operations on the age-specific population migration in South Korean municipalities from 2012 to 2019, taking into account the risk levels of shrinking cities. For this purpose, an analysis was conducted using age-specific net in-migration population as the dependent variable, employing the spatial panel autoregressive model. The research results indicated that the influence of high-speed rail on regional population inflow varies depending on the risk level of shrinking city. In other words, high-speed railway operations had positive effects on population inflow in the capital areas and some major cities, while explained population outflow in the other regions. High-speed railways particularly exerted a significant impact on the inflow of the young and middle-aged population, representing the working age, but this effect was also limited to regions with a low risk of shrinkage. The findings of this study emphasize the importance of considering planned population and industrial attraction when installing high-speed rail with the goal of achieving regional balanced development and mitigating shrinkage. The results of this study also suggest the need for subsequent research to explore factors that positively influence population structure and inflow based on the level of shrinkage risk in each region, as well as the introduction of new policies tailored to the specific situations of each local government.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.655-660
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• 2002

Major deterioration in concrete structures are salt attack and carbonation. Especially severe problems due to carbonation occur in tile concrete structures of city, tunnel, underground structures. Cracks in concrete during service life including early age due to hydration heat and/or shrinkage accelerate the diffusion of concrete so that the deterioration is also accelerated. In this study, carbonation depths of both non-cracked concrete and cracked concrete are evaluated and weight change test and TGA are carried out. Through the tests, a relation between water-cement ratio and carbonation depth is derived and also carbonation increase rate is derived in the function of crack width.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.23 no.2
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• pp.33-47
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• 2020

With population losses and stagnant or depressed economies, the local governments embrace shrinkage and accept having a significantly smaller population. Both the initial and ongoing causes of shrinkage hold dramatic effects on the city and its remaining residents. In this context, vacant land increases as an overabundance of unused infrastructure is demolished and municipalities become burdened with increasing maintenance costs of this land. The result is that vacant land often experiences minimal management relative to social norms and have chance to provide a setting for ecological processes with urban rightsizing strategy. Therefore, urban ecosystems undergo major shifts in structure and function. We need to better understand the possibilities of where and how much of houses and land will be abandoned to assist land planners and policymakers to mitigate conflict between optimal ecological and sociological outcomes. This article, therefore, aims to identify distributional characteristics of vacant houses and lands with case study of Mokpo. The study found and verified affecting factors of vacant houses and lands by type through the use of a Maxent model and spatial data that explained housing choice and preference theory. We can predict the vacancies with the spatial variables such as land price, the population ratio over 65, and the distance from security facility. Based on the analysis, the ways of managing housing and land vacancy for sustainable development and ecological restoration method are discussed.

• Journal of the Korea Concrete Institute
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• v.15 no.2
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• pp.197-208
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• 2003

This paper is to determine the possibility of re-using waste concrete from Incheon city area. The strength test was conducted with five aggregate compounds which was replaced a natural aggregate with recycled aggregate. After checking the physical characteristics of recycled aggregate compounds, the mix design of recycled concrete was conducted. For the relatively comparison between natural and recycled compounds, while the unit aggregate weight was changed, other conditions were fixed. The freezing and thawing test which included fly-ash and super-plastezer were performed to check the durability and workability when recycling waste concrete. In the physical characteristics of recycled aggregate, it was found that the specific gravity of recycled coarse aggregate and recycled fine aggregate satisfied the first grade of recycle specification(KS), and all compounds of recycled aggregate also satisfied the second grade of absorption specification, Especially up to the 50% substitution of recycled aggregate is equal to or a bit lower than that of convention aggregate. In comparison with conventional concrete, the recycled concrete is lower than maximum by 7% in compressive strength decreasing rate after freezing-thawing test. From now, although most of recycled concrete was used to the building lot, subgrade, asphalt admixture, through the result. It was proved that possibility of re-using recycled aggregate as the substructure of bridge, retaining wall, tunnel lining and concrete structure which is not attacked the drying shrinkage severely.