• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.1
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• pp.152-159
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• 2005

For high-speed data communication in band-limited channels, main of the bit error are fading and ISI(Inter-Symbol Interference). The common way of dealing with ISI is using equalization in the receiver. In this thesis, channel adaptive equalizer which uses Fuzzy Stochastic Gradient(FSG) and Constant Modulus Algorithm(CMA) is nonlinear equalizer, or Blind equalizer, that works directly on the signals with no training sequences required. This equalizer employs Takagi-Sugeno's fuzzy model that uses the FSG algorithm, to automatically regulate the step size of the descent gradient vector, combining fast convergence rate and low mean square error(MSE), and the CMA which is a special case of Godard's algorithm, to having multiple dispersion constants($R_p$).

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.1
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• pp.14-25
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• 1995

The main contribution of this paper can be summarized in two items as follws. Firstly, a modelling of mobile communication channel with Rayleigh fading characteristics is presented. Actual signal environments can be approximated as being real measurements by a proper mathematical representation of fluctuation of channel parameters due to Doppler effect, that is determined by the relative speed between transmitter and receiver, and noises, that vary at each sampling time. Secondly, an alternative procedure of synthesizing an adaptive equalizers is presented for recovering original signals that have been corrupted through the modelled channel. In order to compute the optimal tap coefficients for a high speed data(512 k symbol/sec) on a real-time basis, the CGM that guarantees fast and stable convergency is adopted during the training period of each frame. The coefficients obtained by the CGM are used as initial values for the LMS algorithm to trace the optimal coefficients during the data period that vary at each sampling time due to the mobility and noise at the receiver. Using the modelling presented in this paper, distributions of received signal power in various signal environments are demonstrated. The performance of the eqalizer proposed in this paper is shown as a function of BER under the various signal circumstances of mobile communications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.7 s.361
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• pp.53-58
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• 2007

OFDM (orthogonal frequency division multiplexing) is an effective modulation technique for high speed transmission over fading channels. However, it has a high bit error rate in the receiver if there is an error on frame synchronization because of phase rotation. A coherent OFDM system has to acquire exact timing synchronization of fraction and integer sampling positions. When a sampling offset exist the performance of a receiver will be degraded severely. In this paper, we propose an algorithm that acquires the fractional sampling offset in OFDM systems. This scheme compares the channel impulse responses with the early and late sampled signals having 0.5 sample offset from the estimated sampling positions by correlation with the received and training samples. Its performance is verified by computer simulations in multipath channels.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.6
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• pp.949-954
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• 2017

Multiple input, multiple output orthogonal frequency division multiplexing (MIMO OFDM) systems are the candidate for the future wireless communications. However, the main drawback of MIMO OFDM systems is their sensitivity to carrier frequency offset (CFO) similar to the single input, single output OFDM (SISO OFDM) systems. The demodulation of a signal with CFO causes large bit error rate and degrade the performance of a symbol synchronizer. It is important to estimate the frequency offset and minimize or eliminate its impact. In this paper, we propose a technique based on observation training symbols for estimating CFO by employing block-by-block estimation for SISO OFDM systems. The technique of SISO OFDM is extended to the MIMO OFDM systems. Simulation results show that the proposed techniques have a superior performance and better accuracy compared to the conventional techniques in the sense of mean square error.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.57-62
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• 2005

In this paper, we propose a channel estimation method by impulse signal train in OFDM. In order to estimate the channel response, 4 impulse signals are generated and transmitted during one OFDM (Orthogonal Frequency Division Multiplexing) symbol. The intervals between the impulse signals are all equal in time domain. At the receiver, the impulse response signals are summed and averaged. And then, the averaged impulse response signal is zero padded and fast Fourier transformed to obtain the channel estimation. The BER performance of the proposed method is compared with those of conventional estimation method using the long training sequence in fast fading environments. The simulation results show that the proposed method improves by 3 dB in terms of Eb/No, compared with the conventional method.

• International journal of advanced smart convergence
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• v.8 no.1
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• pp.176-183
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• 2019

Rhyme of Truce is an educational program that helps you develop the ability to cope with cyber violence rightly. we aim to produce educational contents that will last a long time in the memory of specially children. By combining the room escape game and Leap motion / VR, the program reflects the user's motion and action in real time. The Keyboard Worrier comes into contact with the user and causes violence, and the user who is attacked by the monster see several negative messages written in red and hears abuses sound. Users enter the virtual space decorated as the cyber world. They can experience cyber-violence indirectly but vividly, and if language violence, which has been overlooked and recognized only as "letters", is executed offline, it will directly wonder if cyber-violence should also be regarded as a means of violence. Users have the opportunity to cope with violence autonomously. When a user is attacked by an in-game monster, there are two ways to choose from. First, fighting against with a keyboard (which is a symbol of language violence) just like a monster. Second, report the abuser to cyber bureau police. Both methods make them to escape the room, but when they get out of the room and return to the home and read the message through the monitor, users can recognize which action was right for.

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.152-173
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• 2021

The Large Banner was introduced during the Japanese Invasions of Korea with a new military system. It was a flag that controlled the movement of soldiers in military training. In addition, it was used in other ways, such as a symbol when receiving a king in a military camp, a flag raised on the front of a royal procession, at the reception and dispatch of envoys, and at a local official's procession. The Large Banner was recognized as a symbol of military dignity and training rites. The Large Banner was analyzed in the present study in the context of two different types of decorations. Type I includes chungdogi, gakgi and moongi. Type II includes grand, medium, and small obangi, geumgogi and pyomigi. Each type is decorated differently for each purpose. The size of the flag is estimated to be a square of over 4 ja long in length. Flame edges were attached to one side and run up and down The Large Banner used the Five Direction Colors based on the traditional principles of Yin-Yang and Five Elements. The pattern of the Large Banner is largely distinguished by four. The pattern of large obangi consists of divine beasts symbolizing the Five Directions and a Taoism amulet letter. The pattern of medium obangi features spiritual generals that escort the Five Directions. The pattern of small obangi has the Eight Trigrams. The pattern of moongi consists of a tiger with wings that keeps a tight watch on the army's doors. As for historical sources of coloring for Large Banner production, the color-written copy named Gije, from the collection of the Osaka Prefect Library, was confirmed as the style of the Yongho Camp in the mid to late 18th century, and it was also used for this essay and visualization work. We used Cloud-patterned Satin Damask as the background material for Large Banner production, to reveal the dignity of the military. The size of the 4 ja flag was determined to be 170 cm long and 145 cm wide, and the 5 ja flag was 200 cm long and 175 cm wide. The conversion formula used for this work was Youngjochuck (1 ja =30cm). In addition, the order of hierarchy in the Flag of the King was discovered within all flags of the late Joseon Dynasty. In the above historical study, the two types of Large Banner were visualized. The visualization considered the size of the flag, the decoration of the flagpole, and the patterns described in this essay to restore them to their original shape laid out the 18th century relics on the background. By presenting color, size, material patterns, and auxiliary items together, it was possible not only to produce 3D content, but also to produce real products.

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.408-416
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• 2017

This researcher looked at the characteristics of "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" acting techniques focused on body expressions and sought to utilize it as training method for modern actors. 'Body postponement as a symbol' is a key characteristic of "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" acting techniques, and each facial expression, gesture, and movement performed by an actor has a specific meaning. Therefore, the study on "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" has been treated as a major study mainly in the non-realistic expression style or the body-centered acting theory. Therefore, a study on "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" acting techniques was mainly dealt with as a major research subject in the nonrealistic expression style or body-centered acting theory. This study, on the other hand, emphasized the importance of research on the utilization plan of actor training, which can be usually used in realistic plays as well as non-realistic plays. According to psychologists such as Damasio and Eckman, internal impulses can also be triggered through expressions and actions associated with emotions. In addition, not only acting through the actor's inner impulse, but also expression of the actor's faithful external emotion can trigger the emotion of the audience. Such a case can be a psychological basis that "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" acting techniques, which defines rasa and expresses it physically, can be used as a methodology to enhance inner truth. Therefore, the study on the actor training utilizing ing "$N\bar{a}tya$ $\acute{s}\bar{a}stra$" can be applied as an effective approach in the study of contemporary acting theory which intends to integrate inner impulse and external expression.

• Journal of Digital Contents Society
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• v.19 no.2
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• pp.251-257
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• 2018

The purpose of this study is to analyze the satisfaction and requirements of users' devices after development of tablet based AAC(Augmentative and Alternatice Communication) application for Android. The purpose of this study is to evaluate the satisfaction and the requirement of tablet - based AAC application, Were assessed using the Korea Assistive Technology Assessment Tool (KAAT). As a result of satisfaction evaluation of tablet-based smart AAC device, all the items including device, service, and everyday life showed positive response satisfying from 5 point scale to more than 4 point scale. However, it was relatively low in the items of effectiveness, manipulation and convenience. Some of the improvements in the application include the enlargement of the symbol sound and the simplicity of symbol editing. The results of the study suggest that continual updates of m Smart AAC applications, the simplicity of symbolic editing, application usage and training should be improved. The satisfaction evaluation results of this study and the feedback of potential users will be the guidelines for improving and complementing the functions of existing smart AAC devices.

• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.145-153
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• 2019

The present study is a discussion in which the flow of 'social and cultural values' inherent in the creative advertising story is considered against Bart's symbolism and the creative symbol system, and attempted to reproduce the work through the cognitive thinking of the inmates. The interaction of correct social and cultural communication is not just a strategy for persuasion and effectiveness. Starting with these issues, I thought that experiencing the 'symbolic production' and 'cognition interpretation' of the most creative, aesthetic and implicit advertising stories was the realization of concrete cultural values. The reason why I pay attention to advertising as a target tool of the original school is that it gives anyone access to the social and cultural values based on the productivity of meaning, the sharing of meaning and social small-call work by paying attention to the most implicit symbols in a short period of time. I also think that with the trend of the times, it is well worth it as a tool of positive communication for social and cultural member harmony and solving future problems. The reality of social and cultural advertising stories conducted in conjunction with the analysis of meaning at the cognitive thought level is very appropriate to apply in creative classes for college students. The Dong-A Ilbo is a discussion that suggested that the work of realizing the cognitive meaning of advertising stories, a "symbol complex" based on creativity in a complex, multi-media era, will become an age-old communication tool to join university students' strategies for solving future problems