• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7C
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• pp.435-442
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• 2011

The MIMO has weak points such as size and cost of systems and the complexity of hardware augment. Thus, the cooperative transmission techniques have been recently discussed briskly and it also solves problems by increase of shadowy area. However, limited cooperation scheme is utilized due to a single-antenna at the destination. The base station is simply equipped with multiple antennas. When the base station has multiple antennas, cooperative diversity and multiplexing schemes can be easily applied in the base station. To guarantee reliability with high throughput, a cooperative hybrid cyclic relay diversity transmission scheme is proposed which can use an arbitrary number of relays without rate loss and a modification of the base station. The presented results show that the proposed schemes can be effectively applied to the existing various MIMO-OFDM communication system.

• Journal of information and communication convergence engineering
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• v.5 no.3
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• pp.185-193
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• 2007

This paper evaluates the performance combining space-time transmit diversity (STTD) and an efficient channel estimator (ECE) for wideband code division multiple access (WCDMA) systems in various mobile channels. Using decision variable (DV), we also derive the analytic bit error rate (BER) and mean square error (MSE) for WCDMA applying ECE for STTD schemes. The simulation results show that the ECE performance is superior to the previous works in [1] as because we use additional pilot diversity which is so called secondary common control physical channel (S-CCPCH). The performance in case of the channel estimator using only one-channel or two-channel is worse than that of an ECE as about the maximum 4 dB at BER 1.0E-3 satisfying voice service over Rician fading channel. Our results show that, even with ICE, an ECE algorithm are effective in improving the output SNR and significantly reduce the error floor. In addition, the simulation results investigated in this paper also reveal that WCDMA combining an ECE and the STTD scheme could provide appreciable performance improvements in Rayleigh fading channel.

• Korean Journal of Plant Taxonomy
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• v.49 no.4
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• pp.275-281
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• 2019

One key step in the plant restoration process is the collection of seeds from the field. For the selection of source populations of target plant species for translocation purposes (reintroduction or reinforcements), several approaches are possible. A practical method involves the use of data from reciprocal transplant studies. If no direct data are available, knowledge of population genetics and the phylogeography of the target species can serve as an alternative. In this short review, we briefly propose guidelines for those collecting seeds for plant species restoration based on population genetics theory, focusing on two main questions: Where does the plant material come from and how are sources designated, and how are seeds efficiently collected from local populations? While genetic data on a larger scale (phylogeography and population genetics) are needed to form a reply to the first question, similar data on a smaller scale (fine-scale genetic structures within populations) are necessary to shed light on the second issue.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.456-462
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• 2011

This paper investigates the outage behavior of peak interference power limited cognitive radio (CR) networks with multiple transmit antennas. In CR-multi-input single-output (MISO) channel, the total transmit power is distributed over the transmitantennas. First, we use the orthogonal space-time codes (STC) to achieve the transmit diversity at CR-receiver (rx) and investigate the effect of the power distribution on the interference power received at the primary-receiver (P-rx). Then, we investigate the transmit antenna selection (TAS) scheme in which the CR system selects the best transmit antenna and allocates all the power to the selected best antenna. Two transmit antenna selection strategies are proposed depending on if feedback channel is available or not. We derive the closed form expressions of outage probability and outage capacity of all schemes with arbitrary number of transmit-antennas. We show that the proposed schemes significantly improve the outage capacity over the single antenna systems in Rayleigh fading environment. We also show that TAS based scheme outperforms the STC based scheme when peak interference power constraint is imposed on the P-rx only if a feedback channel from CR-rx to CR-transmitter is available.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.74-79
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• 2002

This paper shows a reasonable design standard factor in commercial buildings, that was made by the systematic and statistical way considering actual conditions, such as investigated electric equipment capacity, electric power consumption, load characteristic, etc., for 23 commercial buildings. With a rapid growth of national economics with the development of intelligence society , electrical energy consumption markedly increased Expecially, it is increased electrical energy consumption in the commercial buildings and thus an energy conservation through efficient use of electricity became more important In our country, the estimation of demand factor and electric equipment capacity are not properly and thus the application of these factors are confusing and different in each electric design of the field.

• Plant Biotechnology Reports
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• v.2 no.1
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• pp.33-39
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• 2008

In this paper, we would like to show unexpected morphogenic potential of cell suspensions derived from seedling explants of Gentiana kurroo (Royle). Suspension cultures were established with the use of embryogenic callus derived from seedling explants (root, hypocotyl and cotyledons). Proembryogenic mass proliferated in liquid MS medium supplemented with $0.5mg\;l^{-1}$ 2,4-D and $1.0mg\;l^{-1}$ Kin. The highest growth coefficient was achieved for root derived cell suspensions. The microscopic analysis showed differences in aggregate structure depending on their size. To assess the embryogenic capability of the particular culture, 100 mg of cell aggregates was implanted on MS agar medium supplemented with Kin ($0.0-2.0mg\;l^{-1}$), $GA_3$ ($0.0-2.0mg\;l^{-1}$) and AS ($80.0mg\;l^{-1}$). The highest number of somatic embryos was obtained for cotyledon-derived cell suspension on $GA_3$-free medium, but the best morphological quality of embryos was observed in the presence of $0.5-1.0mg\;l^{-1}$ Kin, $0.5mg\;l^{-1}$ $GA_3$ and $80.0mg\;l^{-1}$ AS. The morphogenic competence of cultures also depended on the size of the aggregate fraction and was lower when size of aggregates decreased. Flow cytometry analysis reveled luck of uniformity of regenerants derived from hypocotyl suspension and 100% of uniformity for cotyledon suspension.

• Asia pacific journal of information systems
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• v.20 no.1
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• pp.101-125
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• 2010

This paper uses the status inconsistency theory to identify factors related to team members' (dis)satisfaction with the composition of virtual IT project teams in order to predict their turnover intentions. Our approach is based on the premise that virtual teams, although increasingly popular among global organizations, create an environment replete with cultural and functional diversity. Yet, a paradox exists: increasing diversity in virtual teams maximizes the creation and use of organizational knowledge while simultaneously increasing dissatisfaction and turnover. This is a critical issue in the formation and management of virtual teams. Therefore, we investigate how team members' perceptions of differences among themselves (i.e. foreignness) impact the stability of team membership, leading to what we describe as a 'liability of foreignness.' Findings indicate that a member's perception of foreignness has a detrimental effect on satisfaction with his or her team members while satisfaction is likely to decrease turnover intention. This may be an implication that managers need to maintain a balance in order to discourage member turnover and the loss of key players.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.498-507
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• 2021

Ichthyoplankton (fish eggs and larvae) were collected seasonally collected from 2017 to 2019 to clarify whether Dokdo serves as a fish spawning and/or nursery ground. Fish eggs were identified and classified into 16 species. The dominant fish egg species were Engraulis japonicus, Maurolicus japonicus, and Parajulis poecilepterus. Fish larvae were identified and classified into 15 species. The dominant fish larvae species were E. japonicus, M. japonicus, and Sebastes owstoni. A cluster analysis similarity percentages revealed two distinct groupings according to sample location (stations) with E. japonicus and M. japonicus as the main group influencers. E. japonicus was the dominant species off Dokdo. The species diversity and abundance peaked in summer. The diversity index, richness index, and evenness index fluctuated seasonally. There were no predominant species variations among the years. Sedentary species such as P. poecilepterus, Semicossyphus reticulatus, and Glyptocephalus stelleri occurred in the inshore stations. E. japonicus, M. japonicus, and Trachipterus trachypterus occurred in the offshore stations. Our results show these species use Dokdo as spawning and nursery grounds.

• Environmental Engineering Research
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• v.23 no.4
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• pp.420-429
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• 2018

Soil stabilization is a soil remediation technique that reduces the mobility of heavy metals in soils. Although it is a well-established technique, it is nonetheless essential to perform a follow-up chemical assessment via a leaching test to evaluate the immobilization of heavy metals in the soil matrix. Unfortunately, a standard chemical assessment is not sufficient for evaluation of the biological functional state of stabilized soils slated for agricultural use. Therefore, it is useful to employ a pyrosequencing-based microbial community analysis for the purpose. In this study, a recently stabilized site in the proximity of an exhausted mine was analyzed for bacterial diversity, richness, and relative abundance as well as the effect of environmental factors. Based on the Shannon and Chao1 indices and rarefaction curves, the results showed that the stabilized layer exhibited lower bacterial diversity than control soils. The prevalence of dominant bacterial populations was examined in a hierarchical manner. Relatively high abundances of Proteobacteria and Methylobacter tundripaludum were observed in the stabilized soil. In particular, there was substantial abundance of the Methylobacter genus, which is known for its association with heavy metal contamination. The study demonstrated the efficacy of (micro)biological assessment for aiding in the understanding and post-management of stabilized soils.

• Journal of Ginseng Research
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• v.46 no.1
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• pp.91-103
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• 2022

Background: Red ginseng extract boosts immunity against inflammation and cancer in the human body. However, studies on the effects of red ginseng extract on the gut microbiome remain unexplored. Methods: In 2019, the positive effects and changes in the gut microbiome after administering 1 pack (3 g) of red ginseng extract per day to 53 adults aged 40 to 75 for 24 weeks were investigated. The gut microbial environment changes were qualitatively and quantitatively analyzed using next-generation sequencing and real-time polymerase chain reaction technology. Results: On comparing and analyzing alpha diversity and beta diversity, the microbial pattern showed significant differences (OTUs p = 0.003, chao1 p < 0.001, Bray-Curtis p = 0.001) before and after ingestion of red ginseng extract, indicating that gut microbial richness increased after ingestion. Moreover, after comparing and analyzing the gut microbiome's differences after red ginseng extract intake, significant differences were noted between three strains at the phylum level and among 57 strains at the genus level. Conclusion: This study proposes the potential use of red ginseng extract as a prebiotic after confirming its positive effects, including increasing gut microbiome richness, reducing harm to the gut microbiome, and increasing the number of some strains in the gut microbiome.