• Journal of IKEEE
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• v.15 no.3
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• pp.241-247
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• 2011

In this paper, it was implemented an algorithm of multimedia fingerprinting in DCT block. For the improvement of the limits of DRM’s ability, the proposed algorithm could be decided a responsibility boundary to judge a traitor who falsified the content according to perform separately a watermarking of content provider and a fingerprinting of content user. At the test image size($128{\times}128$) and block size($8{\times}8$) of the content provider, the measured PSNR is Inf~46.6dB with watermarking strength ${\Theta}=0.5{\sim}1.2$, and at a number of users and user's code length are n=7,15,31,63 and l=7,15,31,64 each, the measured PSNR is Inf~46.1 with fingerprinting code length l=7,15,31,63. Finally, a traitor tracing of the falsified content is approached to a trace ratio 1 which is extended to n-1.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.49 no.4
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• pp.16-22
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• 2012

In this paper, the forensic marking algorithm is proposed using psychoacoustic model II and MDCT for high-quality audio. The proposed forensic marking method, that inserts the user fingerprinting code of the audio content into the selected sub-band, in which audio signal energy is lower than the spectrum masking level. In the range of the one frame which has 2,048 samples for FFT of original audio signal, the audio forensic marking is processed in 3 sub-bands. According to the average attack of the fingerprinting codes, one frame's SNR is measured on 100% trace ratio of the collusion codes. When the lower strength 0.1 of the inserted fingerprinting code, SNR is 38.44dB. And in case, the added strength 0.5 of white gaussian noise, SNR is 19.09dB. As a result, it confirms that the proposed audio forensic marking algorithm is maintained the marking robustness of the fingerprinting code and the audio high-quality.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.408-415
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• 2011

A lienor of the real estate Auction procedure does not associate with the lien report truth in an existing law system, and lienor can be opposed to vendee. Malicious lienor abuses such a principle of law and loses a sale price of the deferred purpose real estate in Auction procedure by convenience of lienor. In addition, there is apt to be a case to let I do debtor and collusion and false return, and the Secured credit swell out greatly. The necessity that liability does lien report to assure Secured credi becoming the formation truth and the undertaking of lien in Auction procedure is practically acute need. I showed the legislation idea which switched present situation investigation improvement and lien by the executive officer in legal mortgage in civil law In addition, it revised introduction and the Civil Execution Act of the lien registration system and solved Obligatory Report of the Lien about lien for a legislation.

• Journal of Korea Multimedia Society
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• v.6 no.5
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• pp.861-869
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• 2003

The rapid growth of multimedia network systems has caused overflowing illegal copies of digital contents. Among digital contents, watermarking technique can be used to protect ownership about the image. Copyright protection involves the authentication of image ownership and the identification of illegal copies of image. In this paper, a new digital watermarking technique using HVS and adaptive scale factor based on the wavelet transform is proposed to use the binary image watermark. The original image is decomposed by 3-level wavelet transform. It is embedded to baseband and high frequency band. The embedding in the baseband is considered robustness, the embedding in the high frequency band is concerned about HVS and invisibility. The watermarking of a visually recognizable binary image used the HVS and random permutation to protect the copyright. From the experimental results, we confirm that the proposed technique is strong to various attacks such as joint photographic experts ground(JPEG) compression, cropping, collusion, and inversion of lines.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.10
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• pp.4136-4156
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• 2020

Recently, data can be safely shared or stored using the infrastructure of cloud computing in various fields. However, issues such as data security and privacy affect cloud environments. Thus, a variety of security technologies are required, one of them is security technology using CP-ABE. Research into the CP-ABE scheme is currently ongoing, but the existing CP-ABE schemes can pose security threats and are inefficient. In terms of security, the CP-ABE approach should be secure against user collusion attacks and masquerade attacks. In addition, in a dynamic cloud environment where users are frequently added or removed, they must eliminate user access when they leave, and so users will not be able to access the cloud after removal. A user who has left should not be able to access the cloud with the existing attributes, secret key that had been granted. In addition, the existing CP-ABE scheme increases the size of the ciphertext according to the number of attributes specified by the data owner. This leads to inefficient use of cloud storage space and increases the amount of operations carried out by the user, which becomes excessive when the number of attributes is large. In this paper, CP-ABE access control is proposed to block access of withdrawn users in dynamic cloud environments. This proposed scheme focuses on the revocation of the attributes of the withdrawn users and the output of a ciphertext of a constant-size, and improves the efficiency of the user decryption operation through outsourcing.

• Journal of the Korean association of regional geographers
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• v.11 no.6
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• pp.640-656
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• 2005

A chronic depression in the Korean economy, which depends mostly on imported oil, has been attributed partly to rising crude oil prices recently. Against the backdrop of these realities in Korea, Azerbaijan in the Caspian region, with vast oil and gas deposits, has been greeted enviously by some Koreans. Many transition economies, especially on the Caspian region trumpeted by the oil boom, however, are rich in natural resources, but the benefits of those resources are appropriated by the local elite in collusion with foreign companies. Azerbaijan, in particular, is dominated by a series of internal and external patronage networks. Foreign capital nourishes those networks surrounding President Aliev. Thus, the case of Azerbaijan shows that resource rents in the transition economies sometimes do not help in improving the living conditions of ordinary people. Rather rich resource rents turn out to be a major impediment to the emerging development of the transition economy, lessening the incentives to reform in the country. The result was the possibility of the so-called Dutch Disease, in which disproportionate growth in a certain energy sector tends to crowd out investment in other sectors of the economy.

• Journal of the Korean Geographical Society
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• v.46 no.2
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• pp.233-256
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• 2011

This research is aimed at providing the possibility for overcoming the current people's status of exclusion and fragmented spaces of urban regions. In this context, it needs to be considered that how the social movements, which are in collusion with spatial characteristics, are proceeding in urban societies. In order to find the clue to such problems, this study is going to investigate the social practice especially based on Lefebvre's theory. Because of the abstract characteristics of Lefebvre's issue, an explicit case of that social theory must be contemplated for practical use of his concepts. For the purpose of proposing such practices, this research has been striving to analyze the case of Mullae Art Village through the method of intelviewing the artists of that place and using the statistical data. And then this research has tried to draw the clue about how to overcome the status of exclusion by considering their spatial movements.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.3
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• pp.477-487
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• 2017

Multiparty computation (MPC) is a computation technique where many participants provide their data and jointly compute operations to get a computation result. Earlier MPC protocols were mostly depended on communication between the users. Several schemes have been presented that mainly work by delegating operations to two non-colluding servers. Peter et al. propose a protocol that perfectly eliminates the need of users' participation during the whole computation process. However, the drawback of their scheme is the excessive dependence on the server communication. To cater this issue, we propose a protocol that reduce server communication overhead using the proxy re-encryption (PRE). Recently, some authors have put forward their efforts based on the PRE. However, these schemes do not achieve the desired goals and suffer from attacks that are based on the collusion between users and server. This paper, first presents a comprehensive analysis of the existing schemes and then proposes a secure and efficient MPC protocol. The proposed protocol completely eliminates the need of users' participation, incurs less communication overhead and does not need to solve the discrete logarithm problem (DLP) in order to get the computation results.

• Journal of KIISE:Information Networking
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• v.37 no.5
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• pp.327-338
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• 2010

Complete Subtree scheme(CS) is a well known broadcast encryption scheme to perform group rekeying in a stateless manner. However, statelessness comes at a cost in terms of storage and message overhead in transmitting key material. We propose a Merged Complete Subtree scheme(MCS) to reduce the communication overhead. It is more practical to make broadcast encryption schemes in network environments with limited bandwidth resources. We define all possible subset unions for ever two subsets of CS as new subsets having own key. The modification causes more storage overhead. Nevertheless, it is possible to make the size of a header, including key materials, half using subset unions of MCS, because the size of a header depends on the number of used subsets. Our evaluation therefore shows that the proposed scheme significantly improves the communication overhead of CS, reducing by half the rekey communication cost. The proposed scheme has the advantage of rekey communication cost when the number of revoked users is significant percentage of the number of potential users. The proposed scheme is fully collusion resistant.

• The Journal of Information Systems
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• v.30 no.1
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• pp.123-149
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• 2021

Purpose The purpose of this study is to define the anti-ESG activities of companies recognized by media by reflecting ESG recently attracted attention. This study extracts keywords for ESG controversies through association rule mining. Design/methodology/approach A research framework is designed to extract keywords for ESG controversies as follows: 1) From DeepSearch DB, we collect 23,837 articles on anti-ESG activities exposed to 130 media from 2013 to 2018 of 294 listed companies with ESG ratings 2) We set keywords related to environment, social, and governance, and delete or merge them with other keywords based on the support, confidence, and lift derived from association rule mining. 3) We illustrate the importance of keywords and the relevance between keywords through density, degree centrality, and closeness centrality on network analysis. Findings We identify a total of 26 keywords for ESG controversies. 'Gapjil' records the highest frequency, followed by 'corruption', 'bribery', and 'collusion'. Out of the 26 keywords, 16 are related to governance, 8 to social, and 2 to environment. The keywords ranked high are mostly related to the responsibility of shareholders within corporate governance. ESG controversies associated with social issues are often related to unfair trade. As a result of confidence analysis, the keywords related to social and governance are clustered and the probability of mutual occurrence between keywords is high within each group. In particular, in the case of "owner's arrest", it is caused by "bribery" and "misappropriation" with an 80% confidence level. The result of network analysis shows that 'corruption' is located in the center, which is the most likely to occur alone, and is highly related to 'breach of duty', 'embezzlement', and 'bribery'.