• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.337-340
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• 2005

Rotating annular disks are widely used in data storage devices such as CDs, DVDs(digital versatile disks), and HDs(hard disks). Higher data transfer rate in data storage disks could not be achieved by polycarbonate disks in the present market. The problem can be solved by applying the fiber-reinforce composite materials to the disks. In this paper, an application of composite materials to rotating disks is proposed to increase the critical speed. Dynamic equation is formulated in order to calculate the natural frequency and critical speed for rotating composite by the Galerkin method. The results show that the radially reinforced disk is more effective in increasing critical speed than the circumferentially reinforced disk.

• Journal of Advanced Information Technology and Convergence
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• v.8 no.2
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• pp.89-99
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• 2018

Due to global warming, various natural disasters such as floods and droughts are increasing. If we can detect the possibility of natural disasters in advance, we can prevent massive damages caused by natural disasters. Recent advances in visual sensor technologies have enabled remote monitoring of a variety of natural environments, including lakes, rivers, and shores. In this paper, we propose a method to segment an image obtained from video sensor networks into regions in order to monitor the environment effectively. In the proposed method, we first partition the image into superpixels and model the connections between superpixels as a graph. Then, initial seeds for each region are set by using the prior information, and the initial seeds are expanded to form regions using agglomerative clustering. Experimental results show that the proposed method extracts the regions from natural environment images easily and accurately.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.73-80
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• 2018

Certification revocation list(CRL) is needed for excluding compromised, faulty, illegitimate vehicle nodes and preventing the use of compromised cryptographic materials in vehicular communications. It should be distributed to vehicles resource-efficiently and CRL computational load of vehicles should not impact on life-critical applications with delay sensitive nature such as the pre-crash sensing that affords under 50msec latency. However, in the existing scheme, when a vehicle receives CRL, the vehicle calculates linkage values from linkage seeds, which results in heavy computational load. This paper proposes, a new CRL distribution scheme is proposed, which minimizes the time for CRL processing of vehicles. In the proposed scheme, the linkage value calculation procedure is performed by road-side unit(RSU) instead of the vehicle, and then the extracted linkage values are relayed to the vehicle transparently. The simulation results show that the proposed scheme reduces the CRL computational load dramatically, which would minimize impact on life-critical applications' operations with low latency.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.1
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• pp.11-18
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• 2019

In this paper, we consider interferences from other automobile pulse radars using same frequency spectrum. In order to eliminate the interference, we propose the PN code modulation method. This method uses the cross-correlation between PN codes with different seed. The ROC performance is used for comparing the proposed detector to conventional method. And the proposed detector can decide the present or absent of targets and measure the range of the targets by using memory buffer of range gate. Especially, we use false alarm probability for all range gates. That is the false alarm if in any one range gate the false alarm occurs. From the simulation result, we can see that the proposed detector with using PN code is not influenced by interferences.

• International Area Studies Review
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• v.20 no.1
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• pp.127-146
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• 2016

This paper investigates that the Granger-causality between ODA FDI Trade, and economic growth in Senegal over the last 50 years and ODA, FDI, Trade have a impact on the Senegal's economic growth using the Vector Error Correction Model. The empirical results do confirm a directional causality between the variables considered. It also showed that an increase of ODA in the Senegal has positive effect on GDP growth and FDI, which are important factors of economic growth for poor country like Senegal. Underdeveloped nation has been suffered from insufficient savings or capital for economic growth; therefore, developed nations have to provide enough ODA to supply initial capital formation for growth, so-called, seed money. In a nutshell, ODA as a priming the pump is required and expanded continuously for Africa country's economic growth.

• Journal of Astronomy and Space Sciences
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• v.39 no.2
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• pp.23-33
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• 2022

Electron density irregularities in the equatorial ionosphere at night are understood in terms of plasma bubbles, which are produced by the transport of low-density plasma from the bottomside of the F region to the topside. Equatorial plasma bubbles (EPBs) have been detected by various techniques on the ground and from space. One of the distinguishing characteristics of EPBs identified from long-term observations is the systematic seasonal and longitudinal variation of the EPB activity. Several hypotheses have been developed to explain the systematic EPB behavior, and now we have good knowledge about the key factors that determine the behavior. However, gaps in our understanding of the EPB climatology still remain primarily because we do not yet have the capability to observe seed perturbations and their growth simultaneously and globally. This paper reviews the occurrence climatology of EPBs identified from observations and the current understanding of its driving mechanisms.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.1
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• pp.25-36
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• 2020

Motivation: Fibers as the extracellular filamentous structures determine the shape of the cytoskeletal structures. Their characterization and reconstruction from a 3D cellular image represent very useful quantitative information at the cellular level. In this paper, we presented a novel automatic method to extract fiber diameter distribution through a pipeline to reconstruct fibers from 3D fluorescence confocal images. The pipeline is composed of four steps: segmentation, skeletonization, template fitting and fiber tracking. Segmentation of fiber is achieved by defining an energy based on tensor voting framework. After skeletonizing segmented fibers, we fit a template for each seed point. Then, the fiber tracking step reconstructs fibers by finding the best match of the next fiber segment from the previous template. Thus, we define a fiber as a set of templates, based on which we calculate a diameter distribution of fibers.

• Communications for Statistical Applications and Methods
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• v.31 no.3
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• pp.263-277
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• 2024

This paper proposes new parameterizations of the tilted beta binomial distribution, obtained from the combination of the binomial distribution and the tilted beta distribution, where the beta component of the mixture is parameterized as a function of their mean and variance. These new parameterized distributions include as particular cases the beta rectangular binomial and the beta binomial distributions. After that, we propose new linear regression models to deal with overdispersed binomial datasets. These new models are defined from the proposed new parameterization of the tilted beta binomial distribution, and assume regression structures for the mean and variance parameters. These new linear regression models are fitted by applying Bayesian methods and using the OpenBUGS software. The proposed regression models are fitted to a school absenteeism dataset and to the seeds germination rate according to the type seed and root.

• Korean Journal of Computational Design and Engineering
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• v.6 no.1
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• pp.24-30
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• 2001

An efficient and robust algorithm to compute the exact Voronoi diagram of a circle set is presented. The circles are located in a two dimensional Euclidean space, the radii of the circles are non-negative and not necessarily equal, and the circles are allowed to intersect each other. The idea of the algorithm is to use the topology of the point set Voronoi diagram as a seed so that the correct topology of the circle set Voronoi diagram can be obtained through a number of edge flipping operations. Then, the geometries of the Voronoi edges of the circle set Voronoi diagram are computed. In particular, this paper discusses the topological aspect of the algorithm, and the following paper discusses the geometrical aspect. The main advantages of the proposed algorithm are in its robustness, speed, and the simplicity in its concept as well as implementation. Since the algorithm is based on the result of the point set Voronoi diagram and the flipping operation is the only topological operation, the algorithm is always as stable as the Voronoi diagram construction algorithm of a point set.

• Journal of the Korean Chemical Society
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• v.5 no.1
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• pp.9-14
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• 1961

Ethanol extracts of Mung Bean seeds and seedings were analysed by 2-dimensional and circular paper partion chromatography for Nitrogen compounds as a part of the study on the Amino acids metabolism. In the seeds, 18 ninhydrin positive substances were present, before germination, but the number increased to 21 after germination. There were 3 unknown substances and one of it formed newly after germination. After 2-days germination, the amount of amides, such as Asparagine and Glutamine. where increased very large which were very small amount before it. Those were accumulated more in dark place than in light and the amount of Asparigine were more than that of Glutamine. Through the germination, there were large amount of Glutarmic acid, Aspartic acid and Alanine which seems to be concerned in transamination reaction in seedings. Valine, Leucine, and Phenylalanine increased to considerable amount after germination. This is very remarkable fact as those Amino acids were reported to be concerned in transamination reaction recently. ${\gamma}$-amino butyric acid was detected in both Cotyledon and Embroy through the germination. It seemed that there is no any Nitrogen Metabolism in the unbroken seed even if it is preserved very long period.