• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.2 s.344
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• pp.56-65
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• 2006

In this paper, we introduce modified difference type symbol timing detection method of simple structure and show the relations between S/N ratio and timing detection performance which less influenced by multipath channel delay profile and added noise level and it show very exact GI detection performance characteristics. In the computer simulations, 4 symbol time duration of short and long training of IEEE802.11a standard OFDM frame are used for symbol synchronization timing detection. The computer simulation results show the very exact symbol timing detection performance characteristic within 1 sample error of OFDM signal regardless channel delay profile from minimn phase channels of phase rotation ${\pi}/2$ to non-minimum phase channels of phase rotation ${\pi}/2$ of received OFDM signal and added noise level in channel.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.95-103
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• 2009

An efficient symbol time synchronization scheme for IEEE 802.11n MIMO-OFDM based WLAN systems using cyclic shift diversity (CSD) preamble is proposed. CSD is used to prevent unintentional beamforming when the same preamble signal is transmitted through transmit antennas. However, it is difficult to find a proper starting-point of the OFDM symbol with the conventional algorithms because of time offset by multi-peaks which are result from cross-correlation of received CSD preamble with a known short training symbol. In addition, the performance of symbol time sync. is affected by AGC and packet detection position. In this paper, an optimal symbol time synch. algorithm which is composed of the boundary detection scheme between LTS and OFDM symbols, the verification scheme for enhancement of boundary detection accuracy, and the SNR-varying threshold estimation scheme is proposed. Simulation result show that the proposed algorithm has performance gains of 4.3dB in SNR compared to the conventional algorithms at the rate of 1% sync. failure probability for $2{\times}2$ MIMO-OFDM system and 18dB at 0.1% when maximum frequency offset exists. It also can be applied to $4{\times}4$ MIMO-OFDM system without any modification. Hence, it is very suitable for MIMO-OFDM WLAN systems using CSD preamble.

• The Journal of Korean Medicine
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• v.43 no.2
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• pp.61-74
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• 2022

Objectives: This study aimed to explore the short-term effects of bilateral masticatory training using an intraoral device on memory and concentration, which is an advanced form of Gochi, compared to the unilateral form with gum. Methods: Thirty young healthy participants (age, 16-30 years) were screened and randomly assigned to one of two sequences in a crossover design. The participants assigned to sequence A (n=15) performed bilateral mastication using an intraoral device with a total of 300 taps, followed by unilateral mastication using gum with the same number of repetitions and frequency, separated by a 7-day washout period. A reverse order was used for sequence B. The primary and secondary outcomes were the digit span test result and the symbol digit modality test and the word list recall results, respectively, which were conducted before and after each intervention. Results: Symbol digit modality test scores increased by 12.03±8.33 with bilateral mastication, which was significantly higher than that obtained with chewing gum (5.17 points;95% confidence interval: 0.99, 9.34; p<0.05). Changes in the digit span test and word list recall scores were not significantly different between the two groups. In the digit span test forward, symbol digit modality test, and word list recall test, bilateral mastication was not inferior to unilateral mastication in improving memory and concentration. Conclusions: Bilateral masticatory exercises using an intraoral device are not inferior to unilateral mastication with gum for improving memory in healthy young individuals. Further research is needed to determine the efficacy of bilateral masticatory training on cognitive function.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.980-987
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• 2009

A timing synchronization method is presented for IEEE 802.11a wireless OFDM system. First the signal detection is achieved by measuring the moving energy of the received OFDM signal in two consecutive windows. By measuring the correlation between the short training signal and received envelope signal, fine OFDM symbol synchronization can be acquired. The variance and average value of the correlation value is acquired. And the theoretical values are compared with computer simulation results.

• 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

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11B
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• pp.965-971
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• 2003

This paper suggests a low-complexity frame timing synchronization system for IEEE802.11a wireless LAN systems. The proposed timing synchronization scheme has been implemented by correlating the received OFDM preamble with quantized coefficients composed of ｛0, ${\pm}$2$^{0}$ , ${\pm}$2$^1$‥‥‥ ${\pm}$2$^{i}$ ), where i is an integer number. The 2$^{i}$ -valued coefficients enable the multipliers in the correlation system to be simplified to i-bit shifters. So we can design the correlation system using shifters instead of multipliers. We estimate the performance of the proposed scheme in comparison with conventional systems under the AWGN and Rayleigh fading channels. In this paper we show that the complexity can be reduced by 90% while still maintaining a performance comparable to that of the conventional system.

• Journal of Fashion Business
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• v.6 no.6
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• pp.19-33
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• 2002

In the middle of economic and mental riches in the 21st century, the importance of well being and the pursuit of happiness are emerging as the new trend. Thus the lifestyle that values comfortable and practical naturalness and intrinsic merits has come to influence the human life rather than the old showing-off and formal desire. In addition to this, the spread of the five day week has given more leisure time, which has led to the increasing interest in health and leisure. The interest in sports has skyrocketed since the successful holding of the 2002 Korea and Japan World Cup event. All these changes to the lifestyle have contributed to the fusion of luxury wear and sports wear. As the result of the consumers in the 21st century having more classified and upgraded way of living thanks to the settlement of the above-mentioned lifestyle and the enlargement of the leisure sports culture, there has appeared the wellness kin, who value the importance of life and the nature and believe in the idea that they can reconstruct the environment in the way they can enjoy their lifestyle and pursue happiness. They favor healthy fashion items and think much of exercise, nutrition, and rest. They pursue the natural and comfortable style, whose ideas came from simple exercises such as health training and yoga and the easy and comfortable look observed at resorts. Their fashion style can be divided into three of fitness fashion, yoga fashion and resort fashion. First, the boxer fashion is characterized by the relaxing design and practicality. The major items of the fashion include running shirt-styled upper clothes, training pants, hooded shirts and sneakers. Simple and comfortable look should be induced from the combination of the items. Second, the yoga fashion was motivated by the comfortable yoga wear. It advocates stress-free spirit and comfortable and stable naturalism. Along with the advantages of the good feeling to wear and the functionality to help exercise better, the yoga fashion gives the wearer enough room to move around in, using the unique lines. Third, the resort wear refers to the kinds of clothes you tend to wear at the beach and the park. There are various kinds of the resort look; bathing suits, the beach wear you can wear with the bathing suit, the resort evening wear, the full-side look that you try on top of the bathing suit and is made of the same material of the bathing suit, and the marine look, the symbol of the summer. In short, the study attempted to investigate many trends occurring as the result of human recent increasing interest and concern in the quality of life, and the impacts of them on the fashion world. This kind of research that examines the background of the times and society will help to grasp with the fashion trends of the present and the future. And more studies should be conducted on the development of new and original design in clothes fashion, which reflects the characteristics identified in this kind of research.