• Journal of electromagnetic engineering and science
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• v.7 no.4
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• pp.183-189
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• 2007

When the M-ary signal experiences the Rayleigh fading, the diversity schemes can reduce the effect of fading since the probability that all the signals components will fade simultaneously is reduced considerably. The symbol error probabilities for various M-ary signals, such as MDPSK(M-ary DPSK) and MPSK(M-ary PSK), are mathematically derived for the Selection Combining 2(SC-2) and Selection Combining 3(SC-3) demodulation system which requires a less complex receiver than maximum ratio combining(MRC). The propagation model used in this paper is the frequency-nonselective slow Rayleigh fading channel corrupted by the additive white gaussian noise(AWGN). The numerical results presented in this paper are expected to provide information for the design of radio system using M-ary modulation method for above mentioned channel environment.

• Journal of electromagnetic engineering and science
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• v.7 no.4
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• pp.201-206
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• 2007

When the M-ary signal experiences the Rayleigh fading, the diversity schemes can reduce the effects of fading since the probability that all the signals components will fade simultaneously are reduced considerably. The symbol error probabilities for various M-ary signals, such as MDPSK, MPSK and MQAM, are mathematically derived for the SC-2(Selection Combining 2) demodulation system, whereby the two signals with the two largest amplitudes are coherently combined among the L branches. On the other hand, maximum ratio combining(MRC) requires the individual signals from each path to be time-aligned, cophased, optimally weighted by their own fading amplitude, and then summed. The propagation model used in this paper is the frequency-nonselective slow Rayleigh fading channel corrupted by the Additive White Gaussian Noise(AWGN). The numerical results presented in this paper are expected to provide information for the design of radio system using M-ary modulation method for above mentioned channel environment.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.11a
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• pp.91-95
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• 2001

In this study, we estimated the behavior of the diversity of physiological responses under varied physical environmental factors by measuring variations of heart rate variability (HRV), an index of activity of cardiac autonomic control. Seven healthy young male adults consented and participated in the study. The environmental conditions consisted of thermal, lighting, and acoustic conditions. Two components of HRV were measured. one was the low frequency (LF) component of HRV, which provided a quantitative index of the sympathetic and parasympathetic (vagal) activities controlling the heart rate (HR). The other component measured was the high frequency (HF) component, which provided an index of the vagal tone. The percent contribution of physical environmental factors to the variations in HRV indices were calculated by ANOVA. The contribution of physical environmental factors to the variations in HR was higher than the contribution of HF and LF. However, the contribution of these factors was lower than the contribution related with individual difference in all indices. This result showed that the individual diversity of physiological responses is not a negligible quantity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.81-82
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• 2014

Modular housing has many advantages such as economy, flexibility and reusability. The domestic modular housing of a continuous stacking method has been built in military facilities, and dormitories. However, there is a limit to present diversity of low-rise multi-family housing. A cross stacking method is a way to pursue diversity of that but there is a difficulty to apply it owe to lack of cases and related technologies. Therefore, the purpose of this study is to suggest application techniques in design phase of applying the crossing stacking method in advance.

• Journal of KIISE:Software and Applications
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• v.32 no.1
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• pp.62-73
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• 2005

Evolvable Hardware is the technique that obtains target function by adapting reconfigurable digital' devices to environment in real time using evolutionary computation. It opens the possibility of automatic design of hardware circuits but still has the limitation to produce complex circuits. In this paper, we have analyzed the fitness landscape of evolvable hardware and proposed a speciation technique of evolving diverse individuals simultaneously, proving the efficiency empirically. Also, we show that useful extra functions can be obtained by analyzing diverse circuits from the speciation technique.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.529-535
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• 2022

The purpose of this study is to identify the factors that influence the revisit of jewelry stores. The purpose od this study is to find specific factors that affect product and store satisfaction. The theoretical studies on product quality, perceived quality guarantee, product design, product price, sales promotion, product diversity, store area, store re-visit intent were reviewed. Based on this background, research hypotheses were established. A total of 80 questionnaires were distributed to verify the hypothesis of the study, and 64 were finally used for the analysis. SPSS 24.0 was used for hypothesis verification. The results of this study showed that product quality, perceived product guarantee, product design, and product price had positive influence on product satisfaction. On the other hand, sales promotion, product diversity and store interior were found to have positive influence on store satisfaction. Furthermore, product and store satisfaction were found to have a positive and significant effect on revisit Jewelry Stores.

• Korean Journal of Environment and Ecology
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• v.29 no.1
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• pp.62-68
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• 2015

In order to get basic data for flood plain restoration, we surveyed the woody vegetation in Korean natural rivers and analyzed the species' characteristics with regards to patterns of richness and diversity. These characteristics were higher in hard wood forests than those in soft wood forests, such as Salix spp. community. Futhermore, they were the highest in the Prunus sargentii-Pinus densiflora community(H' 1.095), and the lowest in the Carpinus laxiflora community(H' 0.118) among the hard wood forests. Species' richness diversity were the highest in the Salix gracilistyla community, but the lowest in the S. koriyangi community or S. koreensis community among the soft wood forests. With regards to the dominant index, just one community is over 0.9, 13 communities are between 0.3-0.7 and 15 communities are less than 0.3. The Salix koreensis community was the highest at 0.931, and Prunus sargentii-Pinus densiflora community was the lowest at 0.13. Species' richness and diversity was significantly correlated with tree layer coverages and degree of slope. These results mean that in order to increase plant species diversity in flood plains planted hard woody trees, such as oaks and fir, are needed to suit environmental conditions with steeper slope and lower canopy coverage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.2
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• pp.265-275
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• 2004

In this paper, an OFDM-CDMA broadband system is considered for a possible candidate of fixed wireless broadband access network applications. With an emphasis on a preamble design for multi-channel separation, we address a channel estimation based on the time-domain windowing and its imperfectness in OFDM-based multiple-antenna transmission systems. By properly designing each preamble for multiple antennas to be orthogonal in the time domain, the channel estimation can be applied to the ETSI HlPERLAN/2 and IEEE-802.11a standards in the case of more than two transmit antennas. Also, an effect of diversity techniques on the performance of OFDM-CDMA based broadband wireless access networks is investigated and the maximum achievable diversity gain for a two-path Rayleigh fading environment is evaluated Simulation results show that the OFDM-CDMA system applying a space-time-frequency diversity with a full-rate full diversity code can give the diversity of D = 4 and D = 8 for both multi-user cases of maximum user and half user capacities, respectively.

• The Journal of Information Systems
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• v.30 no.4
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• pp.303-327
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• 2021

Purpose The online comments on news content have become social information and are understood based on deliberative democracy. Although the related research has focused on the relationship between online comments and their deliberative quality, the social information provided by online comments consists of not only direct information such as comments themselves but also indirect information such as 'likes' and 'dislikes'. Therefore, the research on online comments and deliberative quality should study this direct and indirect information together, and the direction and the degree of the indirect information should be also considered with them. Design/methodology/approach This study distinguishes comments by the attached 'likes' and 'dislikes', identifies highly supported and highly unsupported comments by the intensity of 'likes' and 'dislikes', and investigates the relationship between their existence and the deliberative quality measured as the topic diversity. Then, we applied topic modeling to the 2,390 news articles and their 74,385 comments collected from five news sites. Findings The topic diversities of the supported and unsupported comments are related to the topic diversity of all comments but the degree of the relationship is higher in the case of supported comments. Furthermore, the existence of highly supported and unsupported comments is led to less diversity of all comments compared to the case where those comments are absent. Particularly, when only highly supported comments are present, topic diversity was lower than in the opposite case.

• Journal of the Korean Home Economics Association
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• v.47 no.7
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• pp.83-95
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• 2009

This study investigated the differences in the effects of the perception of the internet fashion shopping mall characteristics on satisfaction and loyalty of internet fashion shopping mall between Korean and American college students. Questionnaires were administered to 251 Korean and 221 American college students. The results were as follows. First, service and product diversity had significant effects on satisfaction of internet fashion shopping mall in both group, while convenience had a significant impact on satisfaction of internet fashion shopping mall in American group. Second, service, product diversity, and promotion had significant influences on repurchase intention of internet fashion shopping mall in Korean consumer group, while service and reliability, product diversity, and convenience had significant effects on repurchase intention of internet fashion shopping mall in American consumer group. Third, service had a significant effect on recommendation intention in Korean group, while service and reliability and product diversity had significant influences on recommendation intention in American group.