• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.4
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• pp.259-266
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• 2015

Change detection using the heterogeneous data such as aerial images, aerial LiDAR (Light Detection And Ranging), and satellite images needs to be developed to efficiently monitor the complicating land use change. We approached this problem not relying on the intensity value of the geospatial image, but by using RECC(Relative Edge Cross Correlation) which is based on the edge information over the urban and suburban area. The experiment was carried out for the aerial LiDAR data with high-resolution Kompsat-2 and −3 images. We derived the optimal window size and threshold value for RECC-based change detection, and then we observed the overall change detection accuracy of 80% by comparing the results to the manually acquired reference data.

• Korean Journal of Remote Sensing
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• v.22 no.6
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• pp.613-619
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• 2006

This study proposed an unsupervised image classification through the dendrogram of agglomerative clustering as a higher stage of image segmentation in image processing. The proposed algorithm is a hierarchical clustering which includes searching a set of MCSNP (Mutual Closest Spectral Neighbor Pairs) based on the data structures of RAG(Regional Adjacency Graph) defined on spectral space and Min-Heap. It also employes a multi-window system in spectral space to define the spectral adjacency. RAG is updated for the change due to merging using RNV (Regional Neighbor Vector). The proposed algorithm provides a dendrogram which is a graphical representation of data. The hierarchical relationship in clustering can be easily interpreted in the dendrogram. In this study, the proposed algorithm has been extensively evaluated using simulated images and applied to very large QuickBird imagery acquired over an area of Korean Peninsula. The results have shown it potentiality for the application of remotely-sensed imagery.

• International Area Studies Review
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• v.13 no.3
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• pp.163-190
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• 2009

This study tries to analyze the investment determinants of Chinese firms in local Korea, where the Chinese investing ones have been operating since in the middle of 1990s. The main purpose can be mentioned to test empirically some relations between the investment determinants of Chinese firms and the investment types. In detail speaking, the dependent variables of investment types are classified with sole venture and joint venture, while the independent ones are sorted based on the previous studies with the 2 following factors like the competitive advantages of Chinese firms, and the location advantages of local Korea. This study is conducted as the following: the survey of Chinese firms engaging in investment activities in there is implemented by collecting questionnaires. And for testing the hypothesis, the path analysis of structural equation modeling is activated with SPSS. 12.0 and AMOS 11.0 for windows.

• International Area Studies Review
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• v.12 no.3
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• pp.111-133
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• 2008

This study tries to analyze what the most significant factors are in Russia, where the Korean investing enterprises have to overcome and adapt to various difficulties, especially in terms of local circumstance politically. This main purpose of the research is to test empirically some relations between the managing strategy of Korean enterprises and the circumstance factors of politics in Russia while this is conducted in two stages. First, the research model is designed by reviewing relevant theories, previous studies, and the current investment conditions in local Russia. Second, the survey of Korean enterprises engaged in investment activities in there is done by collecting questionnaires from them with this survey. And the statistic method of structural equation modeling is used to testing some hypotheses. Explaining the analyzing tools, SPSS 12.0 for windows is being used for Correlation, Reliability, Validity and Multi regression and Finally the Path analysis is implemented by AMOS 7.0 for windows.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5179-5202
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• 2018

Transmission Control Protocol (TCP) is the most widely used protocol in the cloud data centers today. However, cloud data centers using TCP experience many issues as TCP was designed based on the assumption that it would primarily be used in Wide Area Networks (WANs). One of the major issues with TCP in the cloud data centers is the Incast issue. This issue arises because of the many-to-one communication pattern that commonly exists in the modern cloud data centers. In many-to-one communication pattern, multiple senders simultaneously send data to a single receiver. This causes packet loss at the switch buffer which results in TCP throughput collapse that leads to high Flow Completion Time (FCT). Recently, Software-Defined Networking (SDN) has been used by many researchers to mitigate the Incast issue. In this paper, a detailed survey of various SDN based solutions to the Incast issue is carried out. In this survey, various SDN based solutions are classified into four categories i.e. TCP Receive Window based solutions, Tuning TCP Parameters based solutions, Quick Recovery based solutions and Application Layer based solutions. All the solutions are critically evaluated in terms of their principles, advantages, and shortcomings. Another important feature of this survey is to compare various SDN based solutions with respect to different performance metrics e.g. maximum number of concurrent senders supported, calculation of delay at the controller etc. These performance metrics are important for deployment of any SDN based solution in modern cloud data centers. In addition, future research directions are also discussed in this survey that can be explored to design and develop better SDN based solutions to the Incast issue.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.4
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• pp.171-178
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• 2019

The use of anti-scatter grids in radiographic imaging has the advantage of preventing the image distortion caused by scattered radiation. However, it carries the side effect of leaving artifacts in the X-ray image. In this paper, we propose a grid line suppression technique using discrete cosine transform(DCT). In X-ray images, the grid lines have different characteristics depending on the shape of the object and the area of the image. To solve this problem, we adopt the DCT transform based on a dynamic segmentation, and propose a filter transfer function for each individual segment. An algorithm for detecting the band of grid lines in frequency domain and a band stop filter(BSF) with a filter transfer function of a combination of Kaiser window and Butterworth filter have been proposed. To solve the blocking effects, we present a method to determine the pixel values using multiple structured images. The validity of the proposed theory has been evaluated from the experimental results using 140 X-ray images.

• The Korean Journal of Emergency Medical Services
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• v.25 no.2
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• pp.19-38
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• 2021

Purpose: This study aimed to investigate the relationship between emergency medical service accessibility in different regions and the sudden death rate in elderly patients with ischemic heart disease using data analysis techniques and suggest improvements in regional emergency medical services. Methods: The study collected data from the NEDIS database and Statistics Korea. Data on a total of 75,867 patients aged ≥65 years were reviewed among patients with ischemic heart disease who visited emergency medical institutions in 2018. Frequency analysis, chi-square test, multiple logistic regression analysis, and simple logistic regression analysis were performed using SPSS PC Window 25.0. Results: With an emergency medical resource per 100km², there was a concomitant reduction in the risk of death. There was a decrease in the death rate by 0.967, 0.970, 0.997, and 0.391 times with the increase in the presence of a fire department, an ambulance, a paramedic, and a regional medical center, respectively. Furthermore, a decrement in the death rate was witnessed 0.844, 0.825, and 0.975 times with the initiation of a local emergency medical center, a local emergency medical institution, and an angiography device, respectively(p <.001). Conclusion: To improve the accessibility of emergency medical services, the population and geometric area of the region should be considered essential factors when deploying emergency medical resources.

• Korean Journal of Metals and Materials
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• v.50 no.12
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• pp.913-920
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• 2012

In spite of some problems in processability and bondability, Au wires in the microelectronics industry are gradually being replaced by copper wires to reduce the cost of raw material. In this article, the effects of surface roughness enhanced capillaries on thermosonic Cu wire bonding were evaluated. The roughness-enhanced zirconia toughened alumina (ZTA) capillaries were fabricated via a thermal grooving technique. As a result, the shear bond strength of first bonds (ball bonds) bonded using the roughness-enhanced capillary was enhanced by 15% as compared with that of normal bonds due to more effective plastic deformation and flow of a Cu ball. In the pull-out test of second bonds (stitch bonds), processed at two limit conditions on combinations of process parameters, the bond strength of bonds formed using the roughness-enhanced capillary also resulted in values higher by 55.5% than that of normal bonds because of the increase in the bonding area, indicating the expansion of a processing window for Cu wire bonding. These results suggest that the adoption of roughness-enhanced capillaries is a promising approach for enhancing processability and bondability in Cu wire bonding.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.1
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• pp.125-133
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• 2011

According to proliferation of mobile devices, security threats have been continuously increased such as illegal or unintentional file transmission of important data to an external mass-storage device. Therefore, we propose a protection method to prohibit an illegal outflow to this device and implement this method. This method extracts signatures from random locations of important file and uses them to detect and block illegal file transmission. To get signatures, a target file is divided by extracting window size and more than one signatures are extracted in this area. To effective signature sampling, various extraction ways such as full, binomial distribution-based and dynamic sampling are implemented and evaluated. The proposed method has some advantages. The one is that an attacker cannot easily predict the signature and its extraction location. The other is that it doesn't need to modify original data to protect it. With the help of these advantages, we can say that this method can increase efficiency of easy-to-use and it is a proper way leakage prevention in a mobile device.

• The Journal of the Convergence on Culture Technology
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• v.8 no.2
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• pp.321-327
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• 2022

Purpose: This study aims to understand the effects of ASMR(The Autonomous Sensory Meridian Response) intervention on university students' anxiety, stress and sleep quality. Method: This study was designed as a One-group pretest-posttest design to measure the effect of ASMR on university students' anxiety, stress and sleep quality. Among university students in the Seoul metropolitan area, 30 students who agreed to the study were selected. Data analysis was performed using SPSS for window version 23.0. Results: The experimental group that provided ASMR intervention showed statistically significant results in levels of anxiety and stress. After ASMR intervention, the experimental group showed statistically significant effects on anxiety(t=5.12, p<.001) (t=5.15, p<.001), stress(t=5.13, p<.001)and sleep quality(t=7.34, p<.001). Conclusion: This study confirms that ASMR has a positive effect on anxiety, stress and sleep quality of university students. Based on these results, it is expected that further research will be conducted on scientific and differentiated ASMR mediation.