• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.643-647
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• 2008

ACE (Advanced Collaboration Environment) [1] aims to provide people to have remote collaboration as they are in the same Space. To provide tele-presence in remote collaboration, quality of audio and sharing of view which can show overall environment. Visual Sharing focuses on providing interactive view sharing among remote participants. A user can see remote collaboration space from any direction and can share his working screen view with others. In this paper, we summarize the development plan of Visual Sharing and relevant elementary techniques for developing Visual Sharing.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.10 no.3
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• pp.37-48
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• 2000

서울Visual cryptography scheme is a simple method in which can be directly decoded the secret information in human visual system without performing any cryptographic computations. This scheme is a kind of secret sharing scheme in which if a secret of image type is scattered to n random images(slides) and any threshold (or more) of them are stacked together the original image will become visible. In this paper we consider (2, n) visual cryptography scheme and propose a new construction method in which the number of expanded pixels can be reduced by using the sample matrix. The proposed scheme can futhermore distribute the multiple secret image to each group according to the difference of relative contrast.

• Journal of the Korea Computer Industry Society
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• v.5 no.9
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• pp.1069-1078
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• 2004

We propose an individual authentication method based on optical visual cryptography in thata fingerprint data is processed by secret sharing method taking into account the optical visual cryptograph and a part of shared data transmitted through an open network. Whenever it is necessary, submitting his fingerprint with the other shared information can authenticate the owner of the fingerprint. The system efficiently identifies fingerprints through optical correlation, regardless of difficulties of acquisition of exact fingerprint imagein the various environments.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1785-1800
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• 2014

In 2011, Chen and Wu proposed their method of sharing n secret images to n+1 shadow images through the concept of a Boolean-based Visual Secret Sharing (VSS) method. However, the shadow images produced by this method are not equally important. If the participant who owns an important shadow image does not want to cooperate with other participants, most secret images can not be reconstructed. In the proposed method, the relationship between the shadows images and secret images are designed in a circular way mostly. Each shadow image only relates to two secret images. This means that if one participant refuses to cooperate with other participants, there are only two secret images which can not be reconstructed. Moreover, our proposed method only needs to produce n shadow images and n secret images can be shared to them.

• The Journal of the Korea Contents Association
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• v.16 no.4
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• pp.275-288
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• 2016

A decision tree analysis was performed by categorizing the idea sketches produced in the group environment into three different levels of visual stimuli ambiguity (vague, ambiguous, and definite) and two idea-sharing situations (before and after). We then examined the predicted values for the creativity of each group's idea sketches, the factors that led to high creativity scores, and their standards. The results of the analyses indicated that the Resistance to Premature Closure, Originality, Elaboration, ness, and Similarity represented important predictors of the creativity of design idea sketches according to the level of ambiguity of the visual stimuli used and whether ideas were shared or not. The group presented with vague stimuli after sharing ideas scored the highest predicted creativity value and the group presented with definite stimuli after sharing ideas scored the lowest predicted creativity value.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.5
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• pp.472-476
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• 2008

In this paper, we propose a simple and user friendly visual secret sharing scheme based on binary image. The proposed scheme is a new information hiding method which uses only bit-wise exclusive-or (XOR) operation and NOT operation to share a secret binary image information in the user friendly binary images. The proposed scheme has the following merits: (1) It provides efficient embedding and reconstruction algorithms. (2) It provides lossless and perfect reconstruction of the secret binary image. (3) It provides the detection method of its own group by sharing the user friendly image. (4) It can share same sized secret image such as original cover image unlike previous methods.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.53-58
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• 2021

Operation of the interleaved Boost PFC converter in Critical Conduction Mode (CrM) shows the advantages of high efficiency and good EMI characteristics owing to the valley switching of FET. However, when it is designed for a highly pulsating load, operation at a relatively high frequency is inevitable at non-pulsating typical load condition, resulting in efficiency degradation. Moreover, the physical size of the inductor becomes problematic because of the nature of the CrM operation, where the inductor peak current is about two times the inductor average current, thereby requiring high DC-bias characteristics, which is worse when the output power is high. In this study, a new parallel driving method of two sets of interleaved boost PFC converters for highly pulsating high-power application is proposed. The proposed method does not require any additional load-sharing controller, resulting in high efficiency and smaller inductor size.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.7
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• pp.3401-3420
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• 2018

Pixel expansion and contrast are two major performance parameters for visual cryptography scheme (VCS), which is a type of secret image sharing. Random Grid (RG) is an alternative approach to solve the pixel expansion problem. Chen and Tsao proposed the first (k, n) RG-based VCS, and then Guo et al., Wu et al., Shyu, and Yan et al. significantly improved the contrast in recent years. However, the investigations on improving the contrast of threshold RG-based VCS are not sufficient. In this paper, we develop a contrast-improved algorithm for (k, n) RG-based VCS. Theoretical analysis and experimental results demonstrate that the proposed algorithm outperformers the previous threshold algorithms with better visual quality and a higher accuracy of contrast.

• Journal of Internet Computing and Services
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• v.17 no.4
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• pp.69-77
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• 2016

Recently, the importance of visual analytics has been recognized in the field of business intelligence. From the view of business intelligence, visual analytics aims for acquiring valuable insights for decision making by interactively visualizing a variety of business information. In this paper, we propose a treemap-based method for visualizing work-sharing relationships among business process performers. A work-sharing relationship is established between two performers who jointly participate in a specific activity of a business process and is an important factor for understanding organizational structures and behaviors in a process-centric organization. To this end, we design and implement a treemap-based visualization tool for representing work-sharing relationships as well as basic hierarchical information in business processes. Finally, we evaluate usefulness of the proposed visualization tool through an operational example using XPDL (XML Process Definition Language) process models.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.3
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• pp.188-194
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• 2020

This paper presents a high-efficiency Switch Mode Line Transformer (SMLT) composed of load-shared dual modules, which is based on the AC/AC LLC resonant converter. Given that the conventional adaptor is usually composed of two power stages, namely, the PFC and DC/DC converters, its system size can be increased according to the output power. However, given that the proposed SMLT can separate the PFC converter from the adaptor, the size reduction of the system can be achieved. Meanwhile, the SMLT with a single module has the limit of the size reduction because of a high resonant current. Thus, it can be configured with dual or multiple modules to reduce the resonant current. Then, their load sharing can be guaranteed by only the proposed transformer structure without an extra current controller. The validity of the proposed converter is proven through a 850-W prototype.