• Smart Structures and Systems
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• v.15 no.3
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• pp.523-541
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• 2015

Structural health monitoring of steel truss bridge based on changes in modal properties was investigated in this study. Vibration measurements with five sensors were conducted at an existing Warren truss bridge with partial fractures in diagonal members before and after an emergency repair work. Modal properties identified by the Eigensystem Realization Algorithm showed evidences of increases in modal damping due to the damage in diagonal member. In order to understand the dynamic behavior of the bridge and possible mechanism of those increases in modal damping, theoretical modal analysis was conducted with three dimensional frame models. It was found that vibrations of the main truss could be coupled internally with local vibrations of diagonal members and the degree of coupling could change with structural changes in diagonal members. Additional vibration measurements with fifteen sensors were then conducted so as to understand the consistency of those theoretical findings with the actual dynamic behavior. Modal properties experimentally identified showed that the damping change caused by the damage in diagonal member described above could have occurred in a diagonal-coupled mode. The results in this study imply that damages in diagonal members could be detected from changes in modal damping of diagonal-coupled modes.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.7-10
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• 1996

The purpose of this experimental investigation is to examine the influence of the catheter on local pressure changes and flow rate in an arterial branch model similar to the femoral artery of man. Effects of branch to main lumen flow rate ratios and the locations of catheter tip were found to be significant on the local pressure changes. Relatively large pressure drops due to obstruction effects may induce endothelial cell damage, which have been reported to be the primary cause of the initiation of the atherosclerosis.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.4
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• pp.1-12
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• 2022

Our study adds to the body of knowledge about the relationship between credit ratings and the capital structure of bond issuers. Using Bloomberg and Datastream databases and employing panel regression models, we study the capital structure changes of Japanese enterprises after credit rating changes by global rating agencies (S&P and Moody's) as well as their local counterparts (R&I and JCR) from 1998 to 2016. We find that after rating downgrades, Japanese enterprises considerably reduce net debt or net debt relative to net equity, similar to the findings of Kisgen (2009), who focused on U.S. industrial firms. They do not, however, make adjustments to their financial structure as a result of rating improvements. In comparison to downgrades by S&P and Moody's, Japanese corporations issue 1.89 percent less net debt and 1.50 percent less net debt relative to net equity after R&I and JCR rating downgrades. To put it another way, Japanese companies consider rating adjustments made by local agencies to be more significant than those made by global rating organizations. Our findings contradict earlier research that suggests S&P and Moody's are more prominent in the investment community than R&I and JCR in Japan.

• Journal of the Korean Society of Food Culture
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• v.37 no.2
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• pp.119-132
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• 2022

The purpose of this study is to examine the changes in the Masan region's restaurant industries from the late 1960s to the early 1980s. Within this period, there were 1,597 numbers of restaurants found in 'Masansanggongmyeonggam'. During the same period, 313 restaurants appeared in the 'Gyeongnamsinmun' restaurant advertisements. The characteristics of the restaurant industry in Masan during this period are as follows. In Korean food, meat menus such as 'Bulgogi' became popular, and local foods such as 'Masan Aguijjim', 'Kkosirak', 'Hoebaekban', and 'Jinjubibimbap' were commercialized. Due to the government's 'Punshik Changny-ö' policy, the flour food became popular and the number of Chinese restaurants rapidly increased. New western foods were also introduced, such as hamburger and pizza. Grilled whole chicken at 'Yeongyangcenter' became popular, and the emergence of 'Food Department Store'. These new changes were introduced so quickly that there was almost no time difference with the metropolitan area, and it is thought that this is because the young people who moved in as the Masan area was industrialized actively accepted the new changes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.5
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• pp.1597-1610
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• 2022

At present, the main method of high-speed train chassis detection is using computer vision technology to extract keypoints from two related chassis images firstly, then matching these keypoints to find the pixel-level correspondence between these two images, finally, detection and other steps are performed. The quality and accuracy of image matching are very important for subsequent defect detection. Current traditional matching methods are difficult to meet the actual requirements for the generalization of complex scenes such as weather, illumination, and seasonal changes. Therefore, it is of great significance to study the high-speed train image matching method based on deep learning. This paper establishes a high-speed train chassis image matching dataset, including random perspective changes and optical distortion, to simulate the changes in the actual working environment of the high-speed rail system as much as possible. This work designs a convolutional neural network to intensively extract keypoints, so as to alleviate the problems of current methods. With multi-level features, on the one hand, the network restores low-level details, thereby improving the localization accuracy of keypoints, on the other hand, the network can generate robust keypoint descriptors. Detailed experiments show the huge improvement of the proposed network over traditional methods.

• Korea journal of population studies
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• v.14 no.2
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• pp.1-17
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• 1991

While various fiscal measures have been used to influence regional capital inflow or industrial location, the effect of fiscal variables on labor mobility has been little understood. Understanding the relationship between the composition of local public and urban migration would enhance the city govenment's ability to pursue an appropriate population policy. In order to examine the potential for local public finance to be utilized as a policy tool in directing urban population growth, this paper analyzes the impact of local government financial structure on urban migration. In examining the data on local government finance and the changes in population of Korean cities during the last ten years, it was found that cities with high per capita expenditure in regional development have experienced high population growth rates. In this study migration equations were constructed using various fiscal variables such as the proportion of special account expenditures which are mostly spent for local development purposes, per capita regional development expenditure, degree of local financial independence and per capita net fiscal benefit, along with other explanatory variables. The results of regression analysis showed that city government's regional development expenditure variables have a positive effect on urban net migration and a negative effect on outmigration. Fiscal independence and per capita net fiscal benefit had mixed effects on in and out migration variables, implying that local tax burden does not consistently deter inmigration or induce outmigration. Based on the results of this study some important policy implications can be found regarding local government's fiscal policies. Those cities seeking to attract higher population inflow should make a greater effort in appropriating local expenditures for regional development purposes such as infrastructure, housing, and transportation. city governments should not be too concerned about high local tax burden or necessarily seek to enhance financial independence for these factors do not exert a clear influence on urban population growth or labor supply.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1925-1932
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• 2000

Damage detection methods using vibration modes are investigated on ring structures and. modal behavior of the slightly asymmetric rings is examined. Mode shapes changes, MSER(modal strain energy ratio) and MCR(modal curvature ratio) are applied to identify the locations of faults or damages. Parameters are calculated and compared by finite element analysis on rings with designed local damages. Damages are modeled as reduced stiffness in the analysis. The results show MSER and MCR can be proper factors to detect local damages in ring structures.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.321-327
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• 2015

In this paper, we propose an algorithm for achieving robust Visual Voice Activity Detection (VVAD) for enhanced speech recognition. In conventional VVAD algorithms, the motion of lip region is found by applying an optical flow or Chaos inspired measures for detecting visual speech frames. The optical flow-based VVAD is difficult to be adopted to driving scenarios due to its computational complexity. While invariant to illumination changes, Chaos theory based VVAD method is sensitive to motion translations caused by driver's head movements. The proposed Local Variance Histogram (LVH) is robust to the pixel intensity changes from both illumination change and translation change. Hence, for improved performance in environmental changes, we adopt the novel threshold estimation using total variance change. In the experimental results, the proposed VVAD algorithm achieves robustness in various driving situations.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.442-446
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• 2004

One of the main issues of government is the development of local areas which have been neglected while major capital was invested on Seoul and its satellite cities. Korean Ministry of Construction and Highway and other government departments are currently working together (or the balanced development of the local areas. Localization which is the balanced development of the Capital and local areas, can be achieved through the balanced development of local industry and technology. It is required to have a strategic approach to the construction technology improvement that is localized and eventually contributes the localization efforts. Construction technology that is associated with the local characteristics is the key factor of the balanced national development. This study includes defining the 'localization' through the investigation of national and international localization examples. Construction technology that reflects the local characteristics is studied in this paper. Local characteristics are identified by (1) surveying 'construction technology demand'; (2) measuring construction technology capability, and (3) studying on government regulation changes. 1'he results provide the fundamental Information for the development of the local construction technology.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.3
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• pp.291-303
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• 2019

This study analyzed the changes in the industrial environment surrounding the Gumi region and the status of the industrial crisis in the Gumi area amid such changes. The Gumi region is experiencing a more turbulent period than ever in the environment changes at the international, national and local levels, such as the transition to the Fourth Industrial Revolution, the weakening of the competitiveness of key industries including mobile devices and displays, and the moving-out of core companies such as Samsung and LG Group. Accordingly, efforts have been made to diversify the industrial structure by fostering industry of automobile parts, high-tech medical devices and carbon materials to cope with and adapt to environmental changes at the regional level. However, the Gumi region is still locked in to the mono-cultural, large enterprise-dependent industrial structure centering on the mobile and display sectors, failing to overcome the regional industrial crisis and stagnating the overall local economy. The relocation of large companies began to increase in the 2010s, reducing the protection of large corporations against environmental changes at the corporate level. As a result, the crisis factors of small and mediumsized enterprises are gradually expanding to the national and international scale and working more complexly, which is beyond the level they can afford. So it is highly likely that the current industrial crisis will deepen. Therefore, it is necessary to strengthen the resilience to adapt to changes in the environment when it comes to overcoming the industrial crisis in Gumi region. To this end, it is necessary to improve innovation capabilities and diversify businesses based on convergence and complex technologies at the enterprise level, and to be selected as a special crisis response area aimed at creating an innovative ecosystem through autonomous resonance of companies and industries at the local level.