• Journal of Ecology and Environment
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• v.35 no.1
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• pp.27-34
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• 2012

Typha angustifolia has ecological characteristics of clonal growth similar to Phragmites australis. The plant spreads byclonal growth and seed dispersal. In this study, for the three stands which have different settlement age at the Baksilji wetland in Korea, genetic diversity was estimated by random amplification of polymorphic DNA analysis to evaluate the change in genetic diversity of T. angustifolia during stand development in the same population. Stand (ST) 1 was the oldest and ST 4 was the youngest. ST 5 was in a small ditch out of the Baksilji. Although the ST 1, ST 2, and ST 3 did not differ significantly in vegetational or physical environment, the genetic diversity estimated according to Nei's gene diversity (h) and the Shannon index (i) increased in the order of ST 1 < ST 2 < ST 3 contrary to formative age. The genetic diversity of ST 4 was much higher than that of the other three stands. ST 4 has similar abiotic environmental conditions with slight T. angustifolia dominance, and seems to be in the early establishment stage. ST 5 differed from the other stands in vegetational and soil environments, which can result in stressful cattail conditions. Even though the ST 5 stand was not younger than the ST 4 stand, ST 5 showed the highest genetic diversity. Our results indicate that after early settlement of the T. angustifolia population, genetic diversity within the species decreased over time and that the decreasing pattern of genetic diversity within T. angustifolia stands is not likely to occur under stressful conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.569-578
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• 2017

The purpose of this study is to investigate the effects of informational diversity-sensitive orientation on employee attitudes, focusing on the moderating effects of communication. Recently, diversity within organizations has intensified and the importance of diversity management within organizations is increasing. Diversity studies have focused on the variance of objective diversity characteristics, and have provided mixed results. In order to overcome limitations in the research, this study focuses on members' perception of diversity. To this end, the variable of informational diversity-sensitive orientation(IDSO) was used. Sample data is derived from 301 surveys of employees in firms located in South Korea. Results show that informational diversity-sensitive orientation(IDSO) had a positive effect on job satisfaction and organizational commitment. Regarding the moderating effect of communication, a positive moderating effect was exhibited only in co-worker communication, and differential influence derived from communication type. Based on the analysis results, we discuss research implications and directions for future research.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1016-1023
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• 2008

Lichens are predominant and important components of flora in the terrestrial ecosystem of Antarctica. However, relatively few researches on the phylogenetic position of Antarctic lichen-forming fungi have been accomplished. In this study, partial sequences of nuclear large subunit rDNAs from 50 Antarctic specimens were obtained and the phylogeny was reconstructed. Antarctic lichen species were distributed in 4 orders, including the monophyletic order Agyrales, paraphyletic orders Pertusariales and Teloschistales, and polyphyletic order Lecanorales. Species diversity was highest in the order Lecanorales, followed by Teloschistales and Pertusariales. Based on the phylogeny and sequence similarity analyses, it is proposed that the taxonomy of Stereocaulon alpinum, Physcia caesia, Usnea aurantiacoatra, and Cladonia species should be revised by careful examination of their phenotypic and molecular characteristics. Six species known to be endemic to Antarctica, Catillaria corymbosa, Himantormia lugubris, Leptogium puberulum, Pertusaria pertusa, Rhizoplaca aspidophora, and Umbilicaria antarctica, formed unique lineages, implying independent origins in the Antarctic area.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.6
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• pp.8-15
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• 2012

In this paper, we investigated possible optical parameters causing deviation of experimentally observed output spectra from theoretically predicted results in a high-order fiber comb filter based on a polarization-diversity loop configuration. They include wavelength dependency of half-wave plates (HWPs) inserted in the filter for wavelength switching and the modal birefringence of single-mode fibers (SMFs) with which optical components comprising the filter are connected. In order to consider the effect of the modal birefringence of the SMF on a filter performance, it is modeled as a low birefringence fiber with an arbitrary orientation angle and birefringence. It is found from the simulation results that the modal birefringence of SMFs strongly affects the spectral characteristics of the filter and decreases the extinction ratio of the filter, compared with the wavelength dependency of HWPs. In particular, it is also confirmed that the spectral deviation and asymmetric distortions of side-lobes in narrow band transmission spectra result mainly from the modal birefringence of SMFs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.6B
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• pp.464-473
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• 2012

In this paper, we derive the gain of network coding when it is utilized for retransmission in wireless networks. To the end, we derive the outage probability of the network-coded transmission and express the diversity order as a function of the number of nodes and the node's listening probability. From the outage probability, we formulate the ${\epsilon}$-outage capacity. The network-coding gain is the ratio of the ${\epsilon}$-outage capacities between network-coded and non-coded transmissions. Under our system model, we find that the network-coding gain is a function of the diversity order. Moreover, when there are infinitely many nodes, we show that the network coding gain approaches $0.25{\epsilon}^{-1}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.2
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• pp.208-216
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• 2001

Signal Fading due to multipath propagation severely impairs the performance of high-speed mobile communication systems. Effective diversity scheme for fading channel is STTD (Space Time Transmitter Diversity) method. This scheme is very simple and using 2 transmit antennas and 1 receive antenna provides a diversity order of two[1],[2]. In this paper, we derive the new probability density function of the envelope of the received signal over correlated Rayleigh fading channel. Using the new pdf of the envelope we analyze the performance of noncoherent M-ary FSK, DPSK and ASKSTTD (Space Time Transmitter Diversity) a system on correlated Rayleigh fading channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.100-109
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• 1993

In this paper, the performance of DS /SSMA BPSK communication system with maximal ratio combining microscopic diversity and selection macroscopic diversity is analyzed. The effects of Rayleigh fading and log normal shadowing on system performance are analyzed, and the validity of microscopic and macroscopic diversity to mitigate the two fading effects are estimated. The increase of the number of chips is effective for mitigating log norma; shadowing, while the increase of the order of microscopic diversity is not. And the higher the standard deviation of shadowing, the more effective the macroscopic diversity.

• Journal of Society of Preventive Korean Medicine
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• v.14 no.1
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• pp.1-12
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• 2010

This research was intended to delve into the diversity of life phenomenon and its characteristics. First of all, this research gave real examples to compare the differences in men's health, disease, and longevity in order to confirm the existence of diversity of life phenomenon. In addition, it also studied the process and mechanism of manifestation of life phenomenon, as well as the influence and problems of existing studies' results and implications. The results are as follow. 1. Differences in health, diseases, and longevity were very big and diverse in researches on different races, nations, ages, socioeconomic status, positions, and even (monozygotic) twins. 2. The basic foundation of all organisms is DNA, and environmental factors change DNA methylation and the structure of chromatin by constantly influencing DNA. Due to this, the manifestation, control, and phenotype of DNA change, resulting in diversified life phenomenon. Therefore, it is the environmental factors, not DNA, that has more influence on the diversity of life. 3. Looking at available studies, the most reasonable perspective on human requires focusing on the diversity of life phenomenon, holistic thinking, and reversible change instead of irreversible determinism. Considerable differences in life phenomenon between entities require a change in malformed perspective on life. Public health and medicine deals with live human beings, a more precise and accurate perspective on life is very important. Because management methods of health and disease, such as structure and approaches of medical research, prevention and cure, must be different by life perspectives.

• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.28-33
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• 2009

In this paper, we evaluate the performance of various diversity techniques which can contribute to provide efficient multimedia broadcasting services via hybrid/integrated satellite and terrestrial network. Space-time coding can achieve the diversity gain in a multi-path environment without additional bandwidth requirement. Recent study results reported that satellite systems can achieve high diversity gains by appropriate utilization of STC and/or forward error correction. Based on these previous study results, we present various cooperative diversity techniques by combing STC and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system. The satellite and several terrestrial repeaters operate in unison to send the encoded signals, so that receiver may realize diversity gain. The results demonstrated in this paper can be utilized in future system implementation.

• Journal of the Korean Institute of Landscape Architecture
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• v.18 no.4
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• pp.7-16
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• 1991

This research investigated soil, plants, insects and birds in the Mongchon Earth Fort, establishing the 11 plots, according to planting treatment, in order to present management method for ecological stability of species in the ground covering plots. The results of analysizing the investigated data summarize as follows. 1. In the ground covering plots without upper layer, the density and coverage of middle and low layer in the natural plots were higher than those in the artificial plots. 2. In the ground covering plots without upper layer, the density and coverage of low layer were higher than those in the artificial, while the density and coverage of herb layer in the natural plots were lower. 3. Whether there was upper layer or not, the total species diversity and enenness of the ground covering community in the natural plot without artificial treatment and natural treatment plot were higher than those ground covering. 4. In the ground covering plots with upper layer, the species diversity of ground covering in the plots without artificial treatment is high, while the species diversity in the plots with natural treatment caused the secondary succession is higher than that of the natural plot. 5. In the ground covering plots without upper layer, the species diversity in the plots with artificial management was higher than that of natural plots, while the evenness in the plots with artificial management was lower. 6. In the ground covering plots with upper layer the species diversity of insect in the plot of natural state was higher than that of insect in the plots with artifical treatment. 7. Synthetically, in the area with upper layer the species diversity of the ground covering community in the natural plot was high, while in the area without upper layer, the species diversity of it in the plots with artificial treatment was high. The insect turned up frequently in the plots of high species diversity of the ground covering, so the bird did in the plots of high species diversity of the ground covering and insects.