• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.1
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• pp.22-30
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• 1994

The error probability of the DS-CDMA / DPSK cellular mobile communication system with CCI canceller and MRC diversity reception technique has been analyzed in the cellular radio channel which is characterized by AWGN, Multi-User Interference(MUI) and m-distribution fading. System capacity i. e., number of user per cell has been derived and the evaluated results are shown in figures as a function of PN code sequence length, fading index, BER, number of diversity branches and $E_b/N_o$, Here, the voice activity factor is assumed to be 3/8, the number of sectors in a cell 3 and Multi-User Iner- ference is modeled as Gaussian process.

• The Plant Pathology Journal
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• v.33 no.2
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• pp.140-147
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• 2017

Fusarium wilts of strawberry, caused by Fusarium oxysporum f. sp. fragariae, is a serious soil-borne disease. Fusarium wilt causes dramatic yield losses in commercial strawberry production and it is a very stubborn disease to control. Reliable chemical control of strawberry Fusarium wilt disease is not yet available. Moreover, other well-known F. oxysporum have different genetic information from F. oxysporum f. sp. fragariae. This analysis investigates the genetic diversity of strawberry Fusairum wilt pathogen. In total, 110 pathogens were isolated from three major strawberry production regions, namely Sukok, Hadong, Sancheong in Gyeongnam province in South Korea. The isolates were confirmed using F. oxysporum f. sp. fragariae species-specific primer sets. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses were executed using the internal transcribed spacer, intergenic spacer, translation elongation factor1-${\alpha}$, and ${\beta}$-tubulin genes of the pathogens and four restriction enzymes: AluI, HhaI, HinP1I and HpyCH4V. Regarding results, there were diverse patterns in the three gene regions except for the ${\beta}$-tubulin gene region. Correlation analysis of strawberry cultivation region, cultivation method, variety, and phenotype of isolated pathogen, confirmed that genetic diversity depended on the classification of the cultivated region.

• Journal of Soil and Groundwater Environment
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• v.25 no.1
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• pp.25-36
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• 2020

In a redox transition zone, geochemical reactions are facilitated by active bacteria that mediate reactions involving electrons, and arsenic (As) and iron (Fe) cycles are the major electron transfer reactions occurring at such a site. In this study, the effect of repetitive redox changes on soil bacterial community in As-contaminated soil was investigated. The results revealed that bacterial community changed actively in response to redox changes, and bacterial diversity gradually decreased as the cycle repeated. Proportion of strict aerobes and anaerobes decreased, while microaerophilic species such as Azospirillum oryzae group became the predominant species, accounting for 72.7% of the total counts after four weeks of incubation. Bacterial species capable of reducing Fe or As (e.g., Clostridium, Desulfitobacterium) belonging to diverse phylogenetic groups were detected. Indices representing richness (i.e., Chao 1) and phylogenetic diversity decreased from 1,868 and 1,926 to 848 and 1,121, respectively. Principle component analysis suggests that repetitive redox fluctuation, rather than oxic or anoxic status itself, is an important factor in determining the change of soil bacterial community, which in turn affects the cycling of As and Fe in redox transition zones.

• Journal of Ecology and Environment
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• v.44 no.3
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• pp.162-177
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• 2020

Background: Ecologists have achieved much progress in the study of mechanisms that maintain species coexistence and diversity. In this paper, we reviewed a wide range of past research related to these topics, focusing on five theoretical bodies: (1) coexistence by niche differentiation, (2) coexistence without niche differentiation, (3) coexistence along environmental stress gradients, (4) coexistence under non-equilibrium versus equilibrium conditions, and (5) modern perspectives. Results: From the review, we identified that there are few models that can be generally and confidently applicable to different ecological systems. This problem arises mainly because most theories have not been substantiated by enough empirical research based on field data to test various coexistence hypotheses at different spatial scales. We also found that little is still known about the mechanisms of species coexistence under harsh environmental conditions. This is because most previous models treat disturbance as a key factor shaping community structure, but they do not explicitly deal with stressful systems with non-lethal conditions. We evaluated the mainstream ideas of niche differentiation and stochasticity for the coexistence of plant species across salt marsh creeks in southwestern Denmark. The results showed that diversity indices, such as Shannon-Wiener diversity, richness, and evenness, decreased with increasing surface elevation and increased with increasing niche overlap and niche breadth. The two niche parameters linearly decreased with increasing elevation. These findings imply a substantial influence of an equalizing mechanism that reduces differences in relative fitness among species in the highly stressful environments of the marsh. We propose that species evenness increases under very harsh conditions if the associated stress is not lethal. Finally, we present a conceptual model of patterns related to the level of environmental stress and niche characteristics along a microhabitat gradient (i.e., surface elevation). Conclusions: The ecology of stressful systems with non-lethal conditions will be increasingly important as ongoing global-scale climate change extends the period of chronic stresses that are not necessarily fatal to inhabiting plants. We recommend that more ecologists continue this line of research.

• Journal of Communications and Networks
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• v.2 no.1
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• pp.76-84
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• 2000

Communication systems, including cell-based mobile communication systems, multiple satellite communication systems of multi-beam satellite systems, require reliable handoff methods between cell-to-cell, satellite-to-satellite of beam-to-team, respectively. Recent measurement of a CDMA cellular system indicates that the system is in handoff at about 35% to 70% of an average call period. Therefore, system reliability during handoff is one of the major system performance parameters and eventually becomes a factor in the overall system capacity. This paper presents novel and improved techniques for handoff in cellular communications, multi-beam and multi-satellite systems that require handoff during a session. this new handoff system combines the soft handoff mechanism currently implemented in the IS-95 CDMA with code and packet diversity combining techniques and an iterative decoding algorithm (Turbo Coding). the Turbo code introduced by Berrou et all. has been demonstrated its remarkable performance achieving the near Shannon channel capacity [1]. Recently. Turbo codes have been adapted as the coding scheme for the data transmission of the third generation international cellular communication standards : UTRA and CDMA 2000. Our proposed encoder and decoder schemes modified from the original Turbo code is suitable for the code and packet diversity combining techniques. this proposed system provides not only an unprecedented coding gain from the Turbo code and it iterative decoding, but also gain induced by the code and packet diversity combining technique which is similar to the hybrid Type II ARQ. We demonstrate performance improvements in AWGN channel and Rayleigh fading channel with perfect channel state information (CSI) through simulations for at low signal to noise ratio and analysis using exact upper bounding techniques for medium to high signal to noise ratio.

• Journal of the Korean Society of Costume
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• v.62 no.8
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• pp.134-148
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• 2012

Social commerce is not only a new form of shopping malls that did not exist in the past, but also a new form of media as it gets combined with social networking services. The purpose of this study is to analyze the influence of clothing involvement on the relationship between shopping values, attitudes, and purchase intentions of consumers in the group-buying type of social commerce. A specialized Internet survey company carried out the survey targeting consumers in their 20s and 30s with experience of purchasing fashion products using group-buying type of social commerce. A total of 200 questionnaires were used for the final analysis. Descriptive statistics, factor analysis, t-test, and regression analysis were conducted by using SPSS 12.0 and AMOS 19.0. The results are as follows. First, diversity/informativeness, impulse/accumulation, price, convenience, reliability, interaction, and adventure were identified as shopping value dimensions. Second, especially in cases of diversity/informativeness, price, and interaction, there were significant differences between the high involvement group and the low involvement group. Third, five of the categories, which were diversity/informativeness, price, convenience, reliability, and interaction, had significant influence on attitude and purchase intention. When the attitude variable was included with shopping value as independent variables in the regression model to predict purchase intention, the attitude variable presented a full mediating effect or a partial mediating effect between shopping value and purchase intention. Also, the relationship among shopping value, attitude, and purchase intention was different to some degree according to the level of consumer clothing involvement.

• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.728-735
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• 2017

Many restoration projects are underway to revive disturbed streams. In order to achieve successful stream restoration, a variety of microhabitats should be created to promote biological diversity. Research on biological classification of microhabitats is essential for biological diversity. However, research on classification using only physical environmental factors has been carried out. The purpose of this study is to classify and quantify the microhabitat of the stream by using macroinvertebrates systematically. In this study, eight wadeable streams and four non-wadeable streams were surveyed to identify the benthic macroinvertebrates in these various microhabitats. Among the physical environmental factors (current velocity, water depth, substrate), the particle size of the substrate was the most influential factor in the emergence of the Habitat Orientaion Groups. Among the HOGs, clinger and burrower were highly correlated with physical environment factors and showed the opposite tendency. The distribution of clinger and burrower according to the physical environmental factors showed two tendencies based on the current velocity (0.3 m/s) and water depth (0.4 m). In addition, the particle size of the substrate showed three trends (${\leq}-5.0$, -5.0 < mean diameter ${\leq}-2.0$, > -2.0). Based on the abundance tendency of these two HOGs, the microhabitats were classified into nine types, from a eupotamic microhabitat to a lentic microhabitat. Classification of the microhabitats using HOGs can be employed for creating microhabitats to promote biological diversity in future stream restoration plans.

• Journal of Broadcast Engineering
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• v.18 no.5
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• pp.749-757
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• 2013

This study aims to find out the influences of user behavior, content characteristics, functional factors and user's perception in cost on user satisfaction and continuous intention in N-Screen service. Web survey was conducted for 498 users who have used N screen service. The results show that the most influential factor contributing to user satisfaction is user interface. VOD diversity, payment system, cost, channel diversity are also meaningful factors. Identifying the critical factors which impact on user satisfaction, this study can provide the basic data for activating OTT service in smart media environment.

• The Journal of the Korea Contents Association
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• v.18 no.1
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• pp.587-595
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• 2018

This research aims to analyze the importance-performance among multiplex cinema selection attributes. Therefore, we collected data for visitors who visited the multiplex cinema and want to watch movies. Of the various multiplex cinema selection attributes, four factors were deduced that includes: major services, human services, physical environment, auxiliary services using exploratory factor analysis. In the quadrant I, the area of 'Concentrate Here' was 'diversity of screening time', 'diversity of movie genre', 'convenience of mobile app use', 'size and convenience of parking facility'. In the quadrant II, 'Keep up the Good Work' area was 'convenience of website booking', 'discounts through card partnerships', 'employee friendliness', 'accurate employee information delivery', 'comfortable seating', 'screen size', 'cinematic sound quality', and 'convenience of traffic' etc. The quadrant III, 'Low Priority' appeared to be 'membership system', 'tidiness of staff attire', 'resting space for waiting time', 'accessibility to the neighboring area', 'diversity of the snack corner', and 'overall cleanliness' etc. The quadrant IV, 'Possible Overkill' was 'appropriateness of the auditorium temperature' and 'service proficiency'.

• Korean Journal of Community Nutrition
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• v.22 no.1
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• pp.13-21
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• 2017

Objectives: This study was conducted to evaluate the nutrition quotient (NQ) by mother's parenting style which may influence the NQ in preschool children. Methods: Subjects were 310 mothers and their 4-6 year old children. The questionnaire composed of demographic characteristics, mother's parenting style at meal time and eating behavior as measured by NQ questions. The NQ questions consisted of 19 food behavior checklist items and all items were grouped into 5 factors: balance, diversity, moderation, regularity, and practice. Mother's parenting style was classified by using words for nutrition education at meal time. All data were statistically analyzed by SPSS program (Ver. 23) and the statistical differences in variables were evaluated by Student's t-test, ${\chi}^2$-test, One-way ANOVA. Results: We observed that in children whose mothers use the parenting style at meal time of 'explanation' and 'compliment & cheer up' had high dietary regularity, diversity, practice. The children of mothers who use the parenting style at meal time of 'persuasion' and 'reward' were found to have a lower degree of balance, diversity, and practice. Especially, children of 'reward' style mothers had lower moderation of dietary life. On the other hand, among the parenting style at meal time of 'comparison & demand', 'treating' and 'faire', there was no significant difference in the NQ factor by each group. NQ grade was higher among those who used more explanation (p < 0.001) and persuasion (p < 0.01) and with use of less persuasion (p < 0.01) and reward (p < 0.01). The positive association observed between the frequency of dietary education of mothers and higher NQ grade indicated the degree of dietary practices of those children. On the other hand, the children of mothers who rarely practice the dietary education at home had lower NQ grade (p < 0.001). Conclusions: In order to promote children's proper dietary behaviors, it is important to provide nutrition education to children as well as provide guidance on parenting style at meal time.