• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.738-746
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• 1995

Greenhouse studies were carried out to find the difference of growth, weed competition and herbicides response in barley(Hordeum vulgare L. emend Larnark) under foggy and non-foggy condition. Plant height, leaf stage, leaf width and shoot fresh weight of barley under foggy condition were greatly increased, while heading rate ripening rate and number of grains per panicle of barley were reduced. Weed emergence based on fresh weight was much greater under foggy than that under non-foggy condition. Plant height of barley under foggy condition was increased comparing with non-foggy condition and significantly reduced with increasing the duration of weed competition, while 1,000-grain weight of barley reduced by the early competition(0∼20 days). Among the herbicides treated, butachlor and thiobencarb inhibited growth of barley under foggy than non-foggy condition. Plant height of barley treated of herbicides under foggy condition was ever increased but 1,000-grain weight of barley was reduced. Weeding efficacy(75-90%) by shoot fresh weight of weeds under foggy condition at 25 days after application was lower 3 to 15% than that under non-foggy condition.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.649-663
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• 1998

The clarify the ecological properties, and to predict change of understory vegetation of mt. Nam Park, population dynamics and interspecific competition of D. smilacinum and D. viridescens, which grow in understory of deciduous broad-leaved forest and pseudo-annuals, were studied from May 20 to May 30 1998. The depth of litter layer, soil moisture content, soil organic matter and soil texture were surveyed in 18 populations (15 D. smilacinum populations and 3 D. viridescens populations). Mean litter layer of d. smilacimum population was thinner than that of D. viridescens populations). Mean litter layer of D. smilacnum population was thinner than that of D. viridescens population. The contents of soil moisture and organic matter of D. smilacinum population were lower than that of D. viridescens population. The D. smilacinum growed in broad range of soil texture but D. viridescens in loamy soil. Because D. smilacinum could tolerate more broad range of soil moisture and soil texture than D. viridescens, the former covered the herb layer in earlier stage and the latter introduced in later stage when rhizome could grow easily. The numbers of individual in two marginal parts were smaller than that in center in same D. smilacinum patch. And the total numbers of individuals grown in (10 ${\times}$ 10)cm were from 0 to 12. The rhizome (subterranean runner) weight, rhizome length, root weight, shoot weight, lea weight and leaf number per subquadrat (cell) increased along the number of individual, that is, increased from marginal part to center. But rhizome weight and rhizome length per individual were vice versa. Therefore, the individuals in marginal part reproduced longer and stronger asexual propagules than that in center. The distribution pattern of D. smilacinum was contageous and that of D. viridescens was random or regular. Therefore, population growth of former was independent on density and that of latter was dependent on density. The distributions of size-class showed normal curves in two population, but the curves based on data of total dry weight showed positive skewness and those of leaf number showed negative skewness The correlation coefficient (CC) values between the properties of each organ were high in two population and significant at 0.1% level. The CC values of D. viridescens were higher of the two. Therefore, the former allocated the energy to each organ stable. The rhizome depth of d. viridescens was 2 times deeper than that of D. smilacinum. And rhizome length and weight of D. viridescens were longer (2 times) or heavier (4 times) than those of D. smilacinum. The patch size of D. viridescens increased 60 cm per year and that of D. smilacinum 30 cm. On this results, the intrinsic increase velocity of d. viridescens patch was 2 times faster than that of d. smilacinum, therefore, on the competition, the former had an advantage over D. smilacinum. The reason why d. viridescens defeated D. smilacinum resulted from that the leaf area of former was 4 times broader than that of latter. in Mt. Nam Park, it was thought that two disporum Population would change with the 3 thpes of environmental change as followings. First, no human impact and increase of soil moisture content resulted in increase of D. viridescens population. Second, mild human impact and similar condition of soil moisture content resulted in slow increase or no changes of D. smilacinum and d. viridescens population. Third, severe human impact and dry condition resulted in decrease or vanishment of two disporum populations.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.228-237
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• 2021

In those day, the Busan local government had instituted a rule to support and enhance competition as well as improve respect for the ship management industry. This study aims to extract the cause factors to enhance such competition using intuitionistic decision making trial and evaluation laboratory (DEMATEL) and interpretive structural modeling (ISM) methods. First, eight factors were extracted from the specifications in the Ship Management Industry Development Act. Second, the intuitionistic fuzzy number was converted to a crisp number using the standard fuzzy number. Third, the influence relationship was analyzed using DEMATEL, and the priority ranks for the factors are determined using ISM. From the results of the impact relationship analysis, the three main cause factors were determined as improvement of technical ship management capability, improvement of expertise of manpower for onshore management, and improvement of the quality of the Korean seafarer. The priorities under the ISM method, in descending order, were as follows: improvement of the quality of Korean seafarers, improvement of professionalism among the manpower for shore management, improvement of technical ship management capability, improvement of commercial ship management capability, establishment of a comprehensive information system, improvement of the working conditions and employment environment for seafarers, financial support such as overseas orders, and strengthening the availability of foreign seafarers. Therefore, it is necessary to prioritize policy promotion based on these factors, especially the top three, as these have the highest impact.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.127-133
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• 1989

An experiment was conducted at the Yeongnam Crop Experiment Station to obtain basic informations about cultural techniques for high yield by manipulating plant spacing in association with seedling number. Cultivars showing relatively low competition index within or between rice hill were Palgongbyeo, Milyang 83. Milyang 90 and Sangpungbyeo, while those with high competition index were Pungsanbyeo, Samgangbyeo, Weongpungbyeo, Taebaegbyeo and Dongjinbyeo. Variations of agronomic characters such as culm length, spikelets per panicle, grain yield per panicle among each culm within hill were not interrelated among the characters. This phenomenon was also same within and between cultivar groups. However, cultivars having high competitive ability showed relatively low variation in agronomic characters. There was a trend that most of rice cultivars had a high positive correlation between total competition index and rice grain yield. Competition index between rice hill was more significant than that of within rice hill for Tongil type cultivars except Milyang 83 which belonged to low tillering capacity while both types of competition index within and between hill were important for Japonica type cultivars and Milyang 83 of Tongil type cultivar to increase rice yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.97-101
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• 1969

The experiment about the mixed sowing of two different growth type varieties of barley-Buheung and Suwon＃18-has been conducted to determine the competition effect between two varieties, and its results are as follows: 1. Buheung-long stem variety-showed higher survived ratio than Suwon＃18-short stem variety- and that tendency was significant under the high fertilized condition. 2. When tow varieties-Buheung and Suwon＃18-were sowed together, the culm length of Buheung was shorter than the single planted Buheung and that of Suwon＃18 was onger than the single planted Suwon＃18, however, the panicle length showed the opposite tendency to the culm length variation. 3. The number of panicles and the number of grains did not show any differences among the treatments. 4. In case of the single sowing, Suwon＃18 showed higher grain yield under the common fertilized condition but Buheung showed significantly increased grain yield under the heavy fertilized condition, however, in case of the mixed towing of two varieties, the grain yield was significantly increased in heavy fertilized plots than standard fertilization. 5. The competition power was significantly superior in Buheung to Suwon＃18 and this tendency was rather definite according to the fertilizer application.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.553-564
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• 2017

We analyzed the effects of government intervention on competition structure of telecommunication companies.. Results showed a decrease in market share difference among mobile telecommunication companies due to increased competition caused by the introduction of mobile virtual network operators (MVNO) and mobile number portability. We also found that the introduction of the MVNO caused a relaxed competition structure between network operators. Furthermore, we observed an increased subscriber influx of late adapters after the introduction of the Mobile and Service Retail Regulation Law (MRL). However, we found a gradual decrease in the competitiveness of MVNO following the introduction of MRL. In addition, the introduction of Mobile and Service Retail Regulation Law had a negative impact on customer churn as well as the financial structures of telecommunication companies.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.5
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• pp.47-56
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• 2023

The Quercus variabilis and Quercus dentata, which are said to be relatively drought tolerant among the important genus Quercus that represent deciduous broad-leaved forests in Korea. These two species are widely distributed worldwide in Korea, Japan and China (northern, central, western and eastern subtropical regions). This study compared the ecological niche breadth and overlap according to growth response in 4 soil moisture gradients for the two species and tried to reveal degree of competition and ecological niche characteristics. The ecological niche breadth was 0.977±0.020 for Q. variabilis and 0.979±0.014 for Q. dentata, the latter being slightly wider. And they were similar in 5 traits (stem length, leaf lamina length, leaf width length, stem weight, leaf petiole weight), Q. variabilis was more dominant in 4 traits (leaves number, stem diameter, leaf area, leaf petiole length), and Q. dentata was more dominant in 7 traits (root length, shoot length, plant weight, root weight, shoot weight, leaf weight, leaf petiole weight). The ecological niche overlap for soil moisture between the two species overlapped most in plant structure-related traits and least in photosynthetic organ-related traits such as petiole length. As a result of principal component analysis, degree of competition between the two species for soil moisture was more severe when the soil moisture condition was low than high. Among the measured traits that affect the two-dimensional distribution, 8 traits (Leaves number, Shoot length, Stem length, Plant weight, Root weight, Shoot weight, Stem weight, Leaves weight) were correlated with the factor 1, and 2 traits (Leaf width length, Leaf petiole weight) were correlated with the factor 2 (r>0.5). These results show that the ecological response of the two species to soil moisture is not a few traits involved, but several traits are involved simultaneously.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.120-122
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• 2006

The paper concerns the hybrid optimization of fuzzy inference systems that is based on Hierarchical Fair Competition-based Parallel Genetic Algorithms (HFCGA) and information data granulation. The granulation is realized with the aid of the Hard C-means clustering and HFCGA is a kind of multi-populations of Parallel Genetic Algorithms (PGA), and it is used for structure optimization and parameter identification of fuzzy model. It concerns the fuzzy model-related parameters such as the number of input variables to be used, a collection of specific subset of input variables, the number of membership functions, the order of polynomial, and the apexes of the membership function. In the hybrid optimization process, two general optimization mechanisms are explored. Thestructural optimization is realized via HFCGA and HCM method whereas in case of the parametric optimization we proceed with a standard least square method as well as HFCGA method as well. A comparative analysis demonstrates that the proposed algorithm is superior to the conventional methods.

• Environmental and Resource Economics Review
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• v.21 no.3
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• pp.627-681
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• 2012

This paper starts with a model of monopolistic competition and endogenous growth, and it adds pollution as an input to production. Then I adopt environmental quality as a renewable resource used in production. I show that increasing returns due to specialization of clean activities as inputs can help lead to sustainable growth with no harm to environmental quality. I also compare and evaluate alternative policy combinations (i.e. taxes +subsidies) that correct two distortions from pollution and monopolistic competition. Finally, I find that, if the productivity of environment in final good production is not sufficiently enough, the number of clean goods tends to increase with more environmental concerns.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.179-187
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• 2019

This study aims to investigate the effects of market commonality and resource similarity on price competition and the recursive consequences in the Korean lodging market. Price comparison among hotels in the same geographic market has been facilitated through the development of information technology, rendering little search cost of consumers. While the literature implies the heterogeneous price attack and response among hotels, a limited number of empirical researches focus on the asymmetric and recursive pattern in the competitive dynamics. This study empirically examines the price interactions in the Korean lodging market based on the theoretical framework of competitive price interactions and countervailing power. Demonstrating superiority to the spatial lag model and the ordinary least squares in the estimation, the results from spatial error model suggest that the hotels with longer operational history pose an asymmetric impact on the price of the newer hotels. The asymmetry is also found in chain hotels over the independent, further implying the possibility of predatory pricing. The findings of this study provide the evidence of a hierarchical structure in the price competition, with different countervailing power by the resources of the hotels. Theoretical and managerial implications are discussed, with suggestions for future study.