• Nuclear Engineering and Technology
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• 제52권5호
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• pp.1013-1021
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• 2020

A combination of simultaneous thermal analysis, evolved gas analysis and non-ambient XRD techniques was used to characterise and investigate the conversion reactions of ammonium uranates into uranium oxides. Two solid phases of the ternary system NH₃ - UO₃ - H₂O were synthesised under specified conditions. Microspheres prepared by the sol-gel method via internal gelation were identified as 3UO₃·2NH₃·4H₂O, whereas the product of a typical ammonium diuranate precipitation reaction was associated to the composition 3UO₃·NH₃·5H₂O. The thermal decomposition profile of both compounds in air feature distinct reaction steps towards the conversion to U₃O₈, owing to the successive release of water and ammonia molecules. Both compounds are converted into α-U₃O₈ above 550 ℃, but the crystallographic transition occurs differently. In compound 3UO₃·NH₃·5H₂O (ADU) the transformation occurs via the crystalline β-UO₃ phase, whereas in compound 3UO₃·2NH₃·4H₂O (microspheres) an amorphous UO₃ intermediate was observed. The new insights obtained on these uranate systems improve the information base for designing and synthesising minor actinide-containing target materials in future applications.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1322-1332
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• 2019

In this paper, we systematically investigated the influence of some selected ligands on the U-phosphate precipitation induced by soil bacteria. These organics are widely ranging from acetate, lactate, salicylate and citrate to oxalate. The results revealed that uranium could be biomineralized on bacteria as $UO_2HPO_4{\cdot}4H_2O$ or $(UO_2)_3(PO_4)_2{\cdot}4H_2O$. The influence of organic ligands on the biomineralization had clear-cut correlations with its complexation abilities to uranyl. It was clearly found that the U-phosphate biomineralization was affected noticeably by the strong ligands (oxalate and citrate). Further study discovered that when the organic ligands were uncompetitive with biotic $PO_4^{3-}$ for uranyl, the transformation of uranyl species from ${\beta}-UO_2(OH)_2$ colloidal particles to free $UO_2^{2+}$-ligands ions could facilitate the U-phosphate biomineralization. However, when the organic ligands competed with biotic $PO_4^{3-}$ for uranyl, the U-phosphate biomineralization were inhibited. Our results highlight the importance of complex interactions of strong organic ligands with uranyl during the bacterial precipitation of U-P compounds and thus for the mobilization and immobilization of radio-nuclides in the nature.

• 한국멀티미디어학회논문지
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• 제19권2호
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• pp.233-239
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• 2016

Color enhancement basically deals with color manipulation in digital images. Recently, the technique has become widely used as a result of the increasing use of digital cameras. Retinex-based colorenhancement algorithms are a popular technique. In this paper, retinex with bilateral filtering is proposed to improve the quality of poorly illuminated images. Generally, it consists of three main steps: first, a retinex-based algorithm with color restoration; second, transformation mapping using histogram matching; and finally, smoothing the image using a bilateral filter. The experimental results demonstrate that the proposed method can successfully enhance image contrast while avoiding the halo effect and maintaining the color distribution in the image.

• Kyungpook Mathematical Journal
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• 제43권4호
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• pp.513-518
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• 2003

In this paper, we have proved a theorem on Hausdorff summability of Fourier series which generalizes various known results. We prove that if $${\int}_{o}^{t}\;{\mid}{\phi}(u){\mid}\;du=o(t)\;as\;t{\rightarrow}0\; and\;\lim_{n{\rightarrow}{\infty}}{\int}^{\eta}_{{\pi}/n}{\frac{{\mid}{\phi}(t)-{\phi}(t+{\pi}/n){\mid}}{t}}dt=o(n)$$ where 0 < ${\eta}$ < 1, then the Fourier series is (H, ${\mu}_n$) summable to s at t = x where the sequence ${\mu}_n$ is given by ${\mu}_n={\int}^1_0x^n{\chi}(x)\;dx\;n=0,1,2\;and\;K_n(t)=\limits\sum_{{\nu}=0}^n(\array {n\\{\nu}})({\Delta}^{{n}-{\nu}}{\mu}_{\nu}){\frac{sin{\nu}t}{t}}$.

• 한국군사과학기술학회지
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• 제17권6호
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• pp.744-750
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• 2014

In this paper, I have measured NCO(Network Centric Operation) Effectiveness of Anti-piracy Operation at the Chunghae Unit. For quantitative analysis, Network Centric Operations Conceptual Framework(U.S Office of Force Transformation) is applied. In accordance with the framework, the Chunghae unit anti-piracy operation scenario is analysed. The scenario is devided with two case(only voice communication and networking). The element of analysis be composed of the organic information, networking, share-ability, and individual information. As a result of analysis, the individual information of first case(only voice) gets 0.59 points. The other side, second case (networking) gets 1 points. This means that NCO has effect on the Chunghae Unit's mission. In addition, I stated the tactics advantage of NCO related a fighting power.

• 한국멀티미디어학회지
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• 제22권1호
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• pp.26-33
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• 2018

The transformation of the processes of governance using the Information and Communication Technologies is aimed at bringing in faster and transparent service delivery, accountability, information sharing and people participation in the decision-making and government processes. The implementation of e-Government requires a comprehensive strategy that is not only sensitive to existing political and economic conditions and realities but is also benchmarked on global best practices. The article reviews the handbook E-Government and Governance Efficiency that provides an insight to research that is being undertaken in the e-Government area, gives an in-depth understanding of critical issues involved in e-Government, and provides expert opinion and recommendations for the Republic of Belarus to augment its potential. It studies the Korean experience on e-Government with special focus on such concepts as e-Government benchmarking, mGovernment, Smart Government and u-Government.

• Journal of the Korean Data and Information Science Society
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• 제28권5호
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• pp.1191-1204
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• 2017

Weighted least squares (WLS) estimation is often easily used for the data with heteroscedastic errors because it is intuitive and computationally inexpensive. However, WLS estimator is less robust to a few outliers and sometimes it may be inefficient. In order to overcome robustness problems, Box-Cox transformation, Huber's M estimation, bisquare estimation, and Yohai's MM estimation have been proposed. Also, more efficient estimations than WLS have been suggested such as Bayesian methods (Cepeda and Achcar, 2009) and semiparametric methods (Kim and Ma, 2012) in heteroscedastic error models. Recently, Çelik (2015) proposed the weight methods applicable to the heteroscedasticity patterns including butterfly-distributed residuals and megaphone-shaped residuals. In this paper, we review heteroscedastic regression estimators related to robust or efficient estimation and describe their properties. Also, we analyze cost data of U.S. Electricity Producers in 1955 using the methods discussed in the paper.

• 한국군사과학기술학회지
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• 제2권1호
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• pp.194-203
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• 1999

This paper presents a measuring technique for bursting height of proximity fuses. This technique uses camera calibration to obtain the perspective transformation matrix describing the projection of the world coordinates to image coordinates, and calculates the world coordinates of bursting points from their image coordinates. The surface approximation algorithm by polynomial functions are also implemented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 C
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• pp.1331-1333
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• 2001

In this study a measurement equipment was designed and made for the nonlinear dielectric constants in dielectrics. The determining method of the nonlinear dielectric constants also was proposed. The measurement equipment was consisted of the wave generation part, the high voltage amplifier part, the measurement part and the data acquisition part. In this equipment the measurement control and the data processing could be conducted by computer. In order to determine the nonlinear dielectric constants alternating sign-wave electric fields are applied to dielectrics with different magnitude and the waves of the electric fields and the response from dielectrics are stored in computer memories. The harmonics of dielectric displacement are obtained by the Fourier transformation of these waves. The nonlinear dielectric constants are determined at the relatively low-field region. The experiment for PZT ceramic samples was done by the equipment and the determining method and as the result meaningful data were obtained.

• 한국문헌정보학회지
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• 제44권4호
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• pp.61-74
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• 2010

By taking a bottom-up "library in the life of the user" perspective rather than a top-down "user in the life of the library" perspective, this paper uses anecdotal evidence from the past and near present to examine the multiple roles the U.S. public library plays and has played as public space in the everyday lives of its patrons. By harnessing "public sphere" theory discussed in Jurgen Habermas's THE STRUCTURAL TRANSFORMATION OF THE PUBLIC SPHERE (1989) and by the examining the rich literatures on civic life and institutions that have evolved from it, the author argues that Library and Information Studies discourse has to expand its scope to include research and analysis of "library as place" from a user's perspective if it hopes to develop a deeper understanding of what the public library does for means to members of the communities in which they reside.