• Journal of Digital Contents Society
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• v.18 no.8
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• pp.1517-1522
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• 2017

Among single image SR techniques, the TV based SR approach seems most successful in terms of edge preservation and no artifacts. But, this approach achieves insufficient SR for texture component. In this paper, we proposed a new TV-G decomposition based SR method to solve this problem. We proposed the SVR based up-sampling to get better edge preservation in the structure component. The NNE used the relaxed constraint to improve the NE. We used the NNE based learning method to improve the resolution of the texture component. Through experimental results, we quantitatively and qualitatively confirm the improved results of the proposed SR method when comparing with conventional interpolation method, ScSR, TV and NNE.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.1152-1162
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• 2019

With the rapid development of the VR industry, many VR contents are produced and circulated, and the need for copyright protection is increasing. In this paper, we propose a method of embedding and extracting watermarks in consideration of VR production process. In embedding, SIFT is performed by selecting the region where distortion is minimized in VR production, and transformed into frequency domain using DWT and embedded into the QIM method. In extracting process, in order to correct the distortion in the projection process, the top and bottom regions are changed to different projection methods and some middle regions are rotated using 3DoF to extract the watermark. After this processing, extracted watermark has higher accuracy than the conventional watermark method, and the validity of the proposed watermark is shown by showing that the accuracy is maintained even in various attacks.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.4
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• pp.99-105
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• 2015

As increasing the use of smart phones, the interest of iOS and Android operating system is growing up. In this paper, a novel steganographic method based on Android platform is proposed. Firstly, we analyze the skia based image format that is supporting 2D graphic libraries in Android operating system. Then, we propose a new data hiding method based on the Android bitmap image format. The proposed method hides the secret data on the four true color areas which include Alpha, Red, Green, Blue. In especial, we increase the embedding capacity of the secret data on the Alpha area with a less image distortion. The experimental results show that the proposed method has a higher embedding capacity and less distortion by changing the size of the secret bits on the Alpha area.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.6
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• pp.171-177
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• 2023

When configuring MDM services only with applications without a central control server, a method that allows security control to be released based on GPS signals in areas sufficiently far from the security area of the workplace is generally applied by embedding and distributing location information of workplaces in MDM applications. This study proposed a method in which each individual directly enters the location information of the security control area needed for them in the distributed app and maintains it as setting information without embedding location information of a specific area such as work in the MDM applications. The method proposed in this study can improve universality, compatibility and the security control level of MDM services, and minimize deployment costs.

• Journal of The Korean Association For Science Education
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• v.40 no.1
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• pp.41-50
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• 2020

Looking at the understanding of scientific concepts from a linguistic perspective, it is very important for students to develop a deep and sophisticated understanding of words used in scientific concept as well as the ability to use them correctly. This study intends to provide the basis for productive knowledge education of scientific words by noting that the foundation of productive knowledge teaching on scientific words is not well established, and by exploring ways to teach the relationship among words that constitute scientific concept in a productive and effective manner. To this end, we extracted the relationship among the words that make up the scientific concept from the text of science textbook by using quantitative text analysis methods, second, qualitatively examined the meaning of the word relationship extracted as a result of each method, and third, we proposed a writing activity method to help improve the productive knowledge of scientific concept words. We analyzed the text of the "Force and motion" unit on first grade science textbook by using four methods of quantitative linguistic analysis: word cluster, co-occurrence, text network analysis, and word-embedding. As results, this study suggests four writing activities, completing sentence activity by using the result of word cluster analysis, filling the blanks activity by using the result of co-occurrence analysis, material-oriented writing activities by using the result of text network analysis, and finally we made a list of important words by using the result of word embedding.

• Journal of Intelligence and Information Systems
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• v.28 no.1
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• pp.131-154
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• 2022

Recently, researches on unstructured data analysis have been actively conducted with the development of information and communication technology. In particular, topic modeling is a representative technique for discovering core topics from massive text data. In the early stages of topic modeling, most studies focused only on topic discovery. As the topic modeling field matured, studies on the change of the topic according to the change of time began to be carried out. Accordingly, interest in dynamic topic modeling that handle changes in keywords constituting the topic is also increasing. Dynamic topic modeling identifies major topics from the data of the initial period and manages the change and flow of topics in a way that utilizes topic information of the previous period to derive further topics in subsequent periods. However, it is very difficult to understand and interpret the results of dynamic topic modeling. The results of traditional dynamic topic modeling simply reveal changes in keywords and their rankings. However, this information is insufficient to represent how the meaning of the topic has changed. Therefore, in this study, we propose a method to visualize topics by period by reflecting the meaning of keywords in each topic. In addition, we propose a method that can intuitively interpret changes in topics and relationships between or among topics. The detailed method of visualizing topics by period is as follows. In the first step, dynamic topic modeling is implemented to derive the top keywords of each period and their weight from text data. In the second step, we derive vectors of top keywords of each topic from the pre-trained word embedding model. Then, we perform dimension reduction for the extracted vectors. Then, we formulate a semantic vector of each topic by calculating weight sum of keywords in each vector using topic weight of each keyword. In the third step, we visualize the semantic vector of each topic using matplotlib, and analyze the relationship between or among the topics based on the visualized result. The change of topic can be interpreted in the following manners. From the result of dynamic topic modeling, we identify rising top 5 keywords and descending top 5 keywords for each period to show the change of the topic. Existing many topic visualization studies usually visualize keywords of each topic, but our approach proposed in this study differs from previous studies in that it attempts to visualize each topic itself. To evaluate the practical applicability of the proposed methodology, we performed an experiment on 1,847 abstracts of artificial intelligence-related papers. The experiment was performed by dividing abstracts of artificial intelligence-related papers into three periods (2016-2017, 2018-2019, 2020-2021). We selected seven topics based on the consistency score, and utilized the pre-trained word embedding model of Word2vec trained with 'Wikipedia', an Internet encyclopedia. Based on the proposed methodology, we generated a semantic vector for each topic. Through this, by reflecting the meaning of keywords, we visualized and interpreted the themes by period. Through these experiments, we confirmed that the rising and descending of the topic weight of a keyword can be usefully used to interpret the semantic change of the corresponding topic and to grasp the relationship among topics. In this study, to overcome the limitations of dynamic topic modeling results, we used word embedding and dimension reduction techniques to visualize topics by era. The results of this study are meaningful in that they broadened the scope of topic understanding through the visualization of dynamic topic modeling results. In addition, the academic contribution can be acknowledged in that it laid the foundation for follow-up studies using various word embeddings and dimensionality reduction techniques to improve the performance of the proposed methodology.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.165-172
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• 2006

In this paper we present a technique for detecting cross-reference points that allows improving watermark detect-ability. In general, Harris detector is commonly used for finding salient points. Harris detector is a kind of combined corner and edge detector which is based on neighboring image data distribution, therefore it has some limitation to find accurate salient points after watermark embedding or any kinds of digital attacks. The new method proposed in this paper used not data distribution but geometrical structure of a normalized image in order to avoid pointing error caused by the distortion of image data. After normalization, we constructed pre-specified number of virtual lines from top to bottom and left to right, and several of cross points were selected by a random key. These selected points specify almost same positions with the accuracy more than that of Harris detector after digital attacks. These points were arranged by a random key, and blocks centered in these points were formed. A reference watermark is formed by a block and embedded in the next block. Because same alteration is applied to the watermark generated and embedded blocks. the detect-ability of watermark is improved even after digital attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.700-705
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• 2006

In this paper, an informed watermarking algorithm is proposed that aids in concealing packet loss errors in video communications. This watermark-based error concealment (WEC) method embeds a low resolution version of the video frame inside itself as watermark data. At the receiver, the extracted watermark is used as a reference for error concealment. The proposed DCT-based algorithm employs informed watermarking techniques in order to minimize the distortion of host frames. At the encoder, a predictive feedback loop is employed which helps to adjust the strength of the data embedding. Furthermore, the distortion of the DCT coefficients introduced in the embedding can be removed to a considerable extent, by employing bit-sign adaptivity. Simulation results on standard video sequences show that the proposed informed WEC scheme has an advantage of 3$\sim$4 dB in PSNR over non-informed WEC and that even a non-informed WEC is still superior to conventional error concealment techniques.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.6
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• pp.81-89
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• 1996

Quantum RF impedance of SIS (superconductor insulator superconductor) junction has been analyzed by using through on tucker's quantum mixer theory in the frequency range form 80 GHz to 120 GHz. The embedding impedance of waveguide-type mixer mount and its equivalent circuit have been evaluated. From these evaluated results, the impedance matching efficiency between mixer mount embedding impedance and mixer port impedance of upper-side band and IF which were determined by augmented admittance matrix with given backshort position has been discussed in detail. It is found that the mixer with fixed backshort mount ahs a impedance matching efficiency about 80% at each port of mixer within 85GHz to 115GHz, which implys a conversion los of mixer would be good enough to be operated such a wide band frequency range. Therefore, the theoretical evaluated results show that our method can be used ot design the mixer mount without any mechanical tuning elements such a backshort or an E-plane tunners for wide band operation.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.7
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• pp.41-47
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• 2011

Recently, digital contents are used a lot due to the rapid development of Internet and the commercialization of smartphones. However variety of attacks, such as collusion attack, can violate the intellectual property rights. BIBD AND-ACC is typical method to protect digital contents from attacks, but it is hard to distribute many users because of the heavy complexity of matrix computation. In this paper, we propose embedding technique to distribute BIBD AND-ACC for many users more than primitive one. We checked the PSNR result as 50.84dB when amplication factor is one and found out the colluders who involved the collusion attack by simulation.