• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.294-295
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• 2011

The fundamental problem of selective protection scheme for encoded bitstreams is to find an efficient algorithm to select the set of frames required to be encrypted that can maximize protection effect with the minimum amount of protected data is required. In this paper, we propose an optimal selective protection scheme for SVC bitstreams by protecting the best combination of frames for selective protection in the sense that the amount of data required for protection is minimized and the resulting visual quality degradation is maximized. The selection of the frames to be encrypted is done by first expressing R-Q (protection rate - visual quality) relationship with Lagragian cost model. The experimental results show that, compared to protecting SVC bitstreams layer by layer, the proposed scheme gives superior performance in terms of protection effectiveness due to its better selection of frames for protection given protection bit budgets.

• International Journal of Contents
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• v.8 no.3
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• pp.79-82
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• 2012

In digital contents distribution environments, a user authentication is an important security primitive to allow only authenticated user to use right services by checking the validity of membership. For example, in Internet Protocol Television (IPTV) environments, it is required to provide an access control according to the policy of content provider. Remote user authentication and key agreement scheme is used to validate the contents accessibility of a user. We propose a novel user authentication scheme using smart cards providing a secure access to multimedia contents service. Each user is authenticated using a subset of attributes which are issued in the registration phase without revealing individual's identity. Our scheme provides the anonymous authentication and the various permissions according to the combination of attributes which are assigned to each user. In spite of more functionality, the result of performance analysis shows that the computation and communication cost is very low. Using this scheme, the security of contents distribution environments in the client-server model can be significantly improved.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1752-1767
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• 2015

As a special type of mobile ad-hoc network, Vehicular Ad-hoc Network (VANET) is considered as an attractive topic by many researchers. In VANETs, vehicles act as routers and clients, which are connected with each other through unreliable wireless links. Due to the dynamic nature of vehicles, developing communication protocols for VANETs is a challenging task. In this paper, we tackle the problem of real-world VANET operations and propose a new dual-level communication scheme through the combination of power and rate control algorithms. Based on the game theoretic approach, the proposed scheme effectively formulates the interactive situation among several vehicles. With a simulation study, it is confirmed that the proposed scheme can achieve better performance than other existing schemes under widely diverse VANET environments.

• Smart Media Journal
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• v.2 no.1
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• pp.31-36
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• 2013

A robust and efficient text extraction is very important for an accuracy of Optical Character Recognition (OCR) systems. Natural scene images with degradations such as uneven illumination, perspective distortion, complex background and multi color text give many challenges to computer vision task, especially in text extraction. In this paper, we propose a method for extraction of the text in signboard images based on a combination of mean shift algorithm and weighting scheme of hue and saturation in HSI color space for clustering algorithm. The number of clusters is determined automatically by mean shift-based density estimation, in which local clusters are estimated by repeatedly searching for higher density points in feature vector space. Weighting scheme of hue and saturation is used for formulation a new distance measure in cylindrical coordinate for text extraction. The obtained experimental results through various natural scene images are presented to demonstrate the effectiveness of our approach.

• Proceedings of the KAIS Fall Conference
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• 2003.11a
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• pp.80-83
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• 2003

A Genetic algorithm is a searching algorithm that based on the law of the survival of the fittest. Multi-population Genetic Algorithms are a modified form of genetic algorithm. Therefore, experience with fuzzy logic and genetic algorithm has proven to be that a combination of them can efficiently make up for their own deficiency. The Multi-population Genetic Algorithms independently evolve subpopulations. In this paper, we suggest a new coding method that independently evolves subpopulations using the fuzzy logic controller. The fuzzy logic controller has applied two fuzzy logic controllers that are implemented to adaptively adjust the crossover rate and mutation rate during the optimization process. The migration scheme in the multi-population genetic algorithms using fuzzy logic controllers is tested for a function optimization problem, and compared with other group migration schemes, therefore the groups migration scheme is then performed. The results demonstrate that the migration scheme in the multi-population genetic algorithms using fuzzy logic controller has a much better performance.

• Journal of Power Electronics
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• v.15 no.2
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• pp.443-454
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• 2015

This study proposes a novel one-cycle control scheme with a plug-in repetitive controller for load compensator. The novelty of this scheme lies in the combination of high dynamics and the simplicity of a one-cycle controller and good steady-state harmonic suppression ability of the repetitive controller. In addition, the proposed scheme can reduce the effect of the harmonics in phase voltage for the existence of the repetitive controller. Finally, experimental results on a three-phase, four-wire, three-level load compensator are reported to validate the effectiveness of the proposed control scheme.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.120-126
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• 2019

This study proposes a neutral voltage balance control scheme for stable fault-tolerant operation of an active neutral point clamped (ANPC) inverter using carrier-based pulse width modulation. The proposed scheme maintains the neutral voltage balance by reconfiguring the switching combination and modulating the reference output voltage in order to solve the degradation of the output characteristic in the fault tolerant operation due to the fault of the power semiconductor switch constituting the ANPC inverter. The feasibility of the proposed control scheme is confirmed by HIL experiment using RT-BOX.

• Fashion & Textile Research Journal
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• v.23 no.4
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• pp.423-438
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• 2021

This study compared and analyzed the direction of Louis Vuitton creative directors Kim Jones and Virgil Abloh. Accordingly, 485 photos(251 Kim Jones, 234 Virgil Abloh) were collected. For data analysis, statistical and content analyses were combined. First, as for the overall design characteristics of creative director Kim Jones, complex colors, colorful barrels, tone-in-tone color schemes, H-line, plain fabrics, soft materials, heterogeneous material combinations, casual style. Second, as for the overall design characteristics of creative director Virgil Abloh, achromatic color, colorful tone, tone-on-tone color scheme, I-line, plain fabric, soft material, similar material combination, casual style. There were significant differences in color, tone, color scheme, silhouette, pattern, material type, material combination, fashion image, detail, trimming, top and bottom that differed in the creative directors' design direction. Therefore, it appears that Kim Jones has been directing the luxurious and unique men's wear through H-line, coat and slim pants, colorful color combination, soft material, heterogeneous material combination, plain fabric, and chic active sensibility. Meanwhile, Virgil Abloh is directing men's wear in a loose and trendy street mood through the I-line, jacket and wide pants, achromatic color, soft material, plain fabric, similar material combinations, and soft and sophisticated modern sensibility.

• Journal of Fashion Business
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• v.13 no.6
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• pp.125-136
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• 2009

The main objective of this research was to understand the characteristics of complementary color scheme through the analysis of contemporary women's fashion color coordination as they appear in the 'Collections'. Data collection of 115 was done through review of 'pr$\hat{e}$t-$\grave{a}$-porter Collections' of four cities; Milan, London, New York, Paris. Statistical analysis of frequency and also qualitative interpretation of characteristics of complementary color harmony characteristics which appeared in four collections were completed. The main findings were as followed; (1) Only 115 complementary color schemes out of 4968 two color combinations appeared. Compared the comparative ratios of appearance frequency between the two color combination and the complementary color harmony, London showed the highest, and followed by New York, and Milan and Paris. (2)The combined color type of 'red+green' was the most frequently appeared, and followed by 'violet+yellow' and 'orange+blue'. For the type of tone harmony, the contrast tone showed the most, and followed by the similarity and identity. According to the type of complementary color combination, the type of tone harmony used differently. Some differences showed in the types of color harmony and tone harmony between collections. (3) The complementary color scheme which shown in four collections harmonized two opposite colors mainly through the strong tone contrast and this could cause tension along with interest in the image. The complementary colors intensified and brought out the attributes each other. More details, high contrast of two complementary colors of yellow and violet created a vibrant look especially when used at higher saturation. Sometimes, however, some tone variations of two hues neutralized the strong effect and sometimes enhanced each other. When they used in similarity tones or identity tones in light colors, the tension was reduced and became softened but still presented nice harmony. In the type of 'red+green' color harmony, the various color combinations were demonstrated, mostly through tone manipulation of green color. The similarity tone harmony, which used the most, could effect a better sense of harmony and present more sophisticated looks. When used in contrast tone harmony, some changes in its own color which have only one color of two the excessive intensity led a good harmony. The 'orange+blue' color harmony was shown the least and used three tone harmony almost the same ratio. In this color harmony, blue amplified its energy and brilliance of orange and seemed to work better when one color was at a lower intensity than the other. In harmony with a similarity and an identity tone, this color harmony produces a stable and calm image. (4) The complementary scheme appeared more frequently in the S/S collections than in A/W collections and showed some differences in the types of color harmony and tone harmony between seasons, however, no big differences between collections.

• Journal of Communications and Networks
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• v.12 no.4
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• pp.366-374
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• 2010

Coded cooperation is a promising user cooperation scheme. In this paper, we first propose a novel network-coding-based coded cooperation scheme. When a user decodes its partner's information correctly in the first frame, it transmits the combination of the partner's parity bits and its own parity bits through network coding in the second frame. This is distinct from the classical scheme, where the user only transmits the partner's parity bits during cooperation. We analyze the outage probability of the proposed scheme, and show that it achieves a full diversity order. Numerical evaluations reveal that the proposed scheme outperforms the classical scheme when the inter-user channel is poor, yet is worse when the inter-user channel is strong. Also, the results show that the proposed scheme always outperforms that of no cooperation in various channel conditions while the performance of classical scheme is worse than that of no cooperation with the poor inter-user channels. This means that the performance of the proposed scheme is more stable than the classical scheme and the proposed scheme is more tolerant to the poor inter-user channels. To combine the advantages of the proposed scheme and the classical scheme under different inter-user channel conditions, we propose an adaptive solution. This adaptive scheme enhances the system performance considerably in all channel conditions in spite of the inter-user channel quality, at the expense of only one acknowledgement or non-acknowledgement bit.