• Journal of the Korean Society for information Management
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• v.25 no.3
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• pp.5-25
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• 2008

Individuals and organizations in the modern society produce diverse digital objects everyday, which are not only valuable information resources at present but also will be invaluable digital heritage for the future generation. TRAC(Trustworthy Repositories Audit & Certification: Criteria & Checklist) is one of the evaluating tools against which digital archives could be assessed for their preparedness to perform the task of long-term preservation. The current study uses TRAC to assess OASIS(Online Archiving & Searching Internet Source). The results show that the web archive has a greater room for strengthening in the object management infrastructure than in organizational and technical infrastructures.

• The KSFM Journal of Fluid Machinery
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• v.18 no.3
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• pp.33-37
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• 2015

A numerical study on the IPM/Bridge Diode cooling and coil cooling has been performed. Results are presented as plots of thermal resistance, temperature drop and RPM-ratio. CFD analysis for conventional cooling system has been performed as a reference case. As the RPM-Ratio was increased, heatsink thermal resistance and coil temperature were decreased. IPM/Bridge Diode thermal resistance and temperature of the coil is tended to be trade-off. The temperature of coil closest to the AC-motor fan showed the most significant change in accordance with duct design. The temperature of coil located at the top of DC-motor fan showed the most significant variation as the cooling air passes the heatsink fin area.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.2
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• pp.29-36
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• 2003

This paper proposes a new 3D image transmission technique using digital watermarking for compatibility with conventional 2D digital TV. To transmit 3D images effectively, generally, we use image sequence transmission using temporal-spatial redundancy between stereo images. It is difficult for users with conventional digital TV to watch the transmitted 3D image sequence because of effectivity of 3D image compression. To improve such problem, in this paper, we perceive the concealment of new information of digital watermarking and conceal information of the other stereo image into three channels of the reference image. So we can watch the image with 3D TV as well as conventional digital TV when it is decoded.

• Asia-Pacific Journal of Business
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• v.14 no.1
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• pp.1-19
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• 2023

Purpose - The purpose of this study was to examine the internal relevance between digital transformation, manipulation of asset evaluation and corporate M&A performance and further explores the impact path of manipulation of asset valuation on corporate M&A performance. Design/methodology/approach - This study based on the financial data of A-share listed companies in Shanghai and Shenzhen Stock Exchanges from 2013 to 2021. Findings - First, manipulation of asset evaluation is negatively correlated with M&A performance. Second, Digital transformation significantly weakens the negative correlation between manipulation of asset evaluation and corporate M&A performance. Third, The effectiveness of internal control plays a partially intermediary role in the process of manipulation of asset evaluation affecting M&A performance. Research implications or Originality - Enriching the existing literature on the subject, the study can also provide useful reference for improving the performance of corporate mergers and acquisitions, regulating asset valuation, promoting the digital transformation of enterprises and improving internal control mechanisms, with both theoretical and practical implications.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.4
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• pp.119-138
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• 2023

This study endeavors to delineate the essential components of digital preservation policies requisite for data repositories. Drawing from an examination of digital preservation policies from data repositories accredited by CoreTrustSeal in 2023, this study unveils the pivotal components intrinsic to a digital preservation policy framework, subsequently elucidating the content each component encompasses. The proffered framework is anticipated to serve as a foundational reference for institutions aiming to craft their digital preservation policies, transcending the confines of those solely pursuing CoreTrustSeal certification, to encompass both domestic and international institutions irrespective of their intent to seek CoreTrustSeal certification.

• Journal of architectural history
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• v.32 no.6
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• pp.63-75
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• 2023

Based on my attendance at the CIPA International Symposium(CIPA2023) organized by the International Scientific Committee on Heritage Documentation(ICOMOS), this paper explored research cases applying digital technologies, including BIM, to architectural heritage. The researches presented at this symposium were categorized into specific areas: data acquisition, data management, data sharing&experience. Through this classification, an analysis of research cases in architectural heritage utilizing digital technology was conducted. By categorizing the 43 academic papers from the CIPA2023 based on research themes, trends in the digital architecture field were analyzed, providing insights into future research directions for the digital acquisition, management, sharing, and experiential aspects of Korean architectural heritage. In conclusion, it is deemed necessary to reference and supplement the methodologies, including algorithms, workflows, and approaches developed in each study, to effectively apply methodologies suitable for the characteristics of Korean architectural heritage and its data.

• Current Optics and Photonics
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• v.3 no.2
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• pp.119-127
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• 2019

A new secret-key-sharing cryptosystem using optical phase-shifting digital holography is proposed. The proposed secret-key-sharing algorithm is based on the Diffie-Hellman key-exchange protocol, which is modified to an optical cipher system implemented by a two-step quadrature phase-shifting digital holographic encryption method using orthogonal polarization. Two unknown users' private keys are encrypted by two-step phase-shifting digital holography and are changed into three digital-hologram ciphers, which are stored by computer and are opened to a public communication network for secret-key-sharing. Two-step phase-shifting digital holograms are acquired by applying a phase step of 0 or ${\pi}/2$ in the reference beam's path. The encrypted digital hologram in the optical setup is a Fourier-transform hologram, and is recorded on CCDs with 256 quantized gray-level intensities. The digital hologram shows an analog-type noise-like randomized cipher with a two-dimensional array, which has a stronger security level than conventional electronic cryptography, due to the complexity of optical encryption, and protects against the possibility of a replay attack. Decryption with three encrypted digital holograms generates the same shared secret key for each user. Schematically, the proposed optical configuration has the advantage of producing a kind of double-key encryption, which can enhance security strength compared to the conventional Diffie-Hellman key-exchange protocol. Another advantage of the proposed secret-key-sharing cryptosystem is that it is free to change each user's private key in generating the public keys at any time. The proposed method is very effective cryptography when applied to a secret-key-exchange cryptosystem with high security strength.

• Journal of Cadastre & Land InformatiX
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• v.44 no.1
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• pp.127-138
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• 2014

It can be effective to extract and apply the updated information from the newly updated map data for updating road data of topographic map. In this study, update target data and update reference data are overlaid and the update objects are explored using network matching technique. And the network objects are classified into five matching and update cases and the update processes for each case are applied to the test data. For this study, road centerline data of digital topographic map is used as an update target data and road data of Korean Address Information System is used as an update reference data. The buffer-based network matching method is applied to the two data and the matching and update cases are classified after calculating the overlaid ratio of length. The newly updated road centerline data of digital topographic map is generated from the application of update process for each case. As a result, the update information can be extracted from the different map dataset and applied to the road network data updating.

• The Journal of Advanced Prosthodontics
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• v.12 no.3
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• pp.173-180
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• 2020

PURPOSE. This study compared digital (reference point matching) and replica methods for measuring marginal and internal fit of full coverage restorations. MATERIALS AND METHODS. A maxillary left first molar typodent was fixed on to an aluminum base and prepared to receive all-ceramic full coverage restoration. The model was scanned with an intraoral scanner (CEREC Omnicam, Sirona, York, PA, USA). Twelve crowns were fabricated from lithium disilicate blocks (IPS emax CAD, Ivoclar Vivadent) and then crystalized. Marginal and internal fit of each restoration was measured by two examiners using replica and a new digital three-dimensional technique. Reliability between the two methods and two examiners was assessed by correlation and Cronbach's Alpha coefficient (P<.05). A Bland-Altman assessment for agreement was used to compare the two methods. RESULTS. Bland-Altman assessment showed that the mean of difference for marginal, absolute marginal, and axial gap was respectively -1.04 ㎛, -41.9 ㎛, and -29.53 ㎛ with limit of agreement (LOA) between -37.26 to 35.18 ㎛ for marginal, -105.85 to 22.05 ㎛ for absolute marginal and -80.52 to 22.02 ㎛ for axial gap. Positive correlation for repeatability (P<.05) in determining marginal and internal gaps by the two examiners in both techniques was revealed. Reliability of both techniques in all sites of measurements was at least good (0.8 ≤ α < 0.9). CONCLUSION. Both measuring techniques appeared highly reliable for evaluating fit of fixed dental restorations, while reference point matching provided higher values in axial and absolute marginal gap assessment.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1272-1280
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• 2008

In this paper, we have proposed a phase noise model of fast frequency hopping synthesizer with DDS Driven PLL architecture. To accurately model the phase noise contribution of noise sources in frequency hopping synthesizer, they were investigated using model of digital divider for PLL, DAC for DDS and Leeson's model for reference oscillator and VCO. Especially it was proposed that the noise component of low pass filter was considered together with the phase noise of VCO. Under assuming linear operation of a phase locked loop, the phase noise transfer functions from noise sources to the output of synthesizer was analyzed by superposition theory. The proposed phase noise prediction model was evaluated and its results were compared with measured data.