• Journal of the Korea Society for Simulation
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• v.21 no.2
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• pp.1-9
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• 2012

Subterranean termites forage by constructing tunnel networks in soil and encounter food resources during tunnel excavation. Some species of termites can travel up to 150 m underground. They often travel to the surface to find wood cellulose to feed their colony, which in turn causes extensive damage to wooden architecture, such as timber-frame houses. This type of damage has been constantly increasing along with global warming because higher temperatures provide an ecological niche for termites. The damage is closely related to termite territory size and distribution. Recently, as a way to research termite control, the necessity of a mathematical model to simulate termite territory formation in relation to damage has increased. So far, however, few studies have been conducted on the development of a model because it is difficult to quantify or characterize the relationship between territorial behavior and field conditions including complicated environmental factors. In the present study, we suggest a simulation model of the territoriality of the Formosan subterranean termites, Coptotermes formosanus (Shiraki), and Reticulitermes flavipes (Kollar), based on empirical data. The model consists of 2 procedures. One describes tunnel network growth for each colony, and the other represents territoriality based on tunnel-tunnel interactions between different colonies. Using the model, we show changes in territorial competition according to the termination probability of tunnel growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.156-164
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• 1990

A field experiment was conducted to study both the distribution characteristics of photosynthetically active radiation (PAR) in the soybean canopy and their relationships with dry matter production. The soybean cultivars 'Hwanggeumkong' and 'Paldalkong' were sown with the spaces of 60$\times$15cm and 30$\times$15cm at Suwon on May 20 and on June 20 in 1989. The ratio of PAR to the total shortwave radiation was estimated by the empirical equation derived from sunshine hours and direct incoming radiation. The functional relationships between the PAR interception and the leaf area index were expressed as a function of Beer's law. The extinction coefficients(k) in the functions ranged from 0.77 to 0.92. The values of k were greater at higher planting density, but they were affected neither by planting dates nor by varieties. The reflection ratio of PAR($\alpha$) was determined by the exponential function as below; $\alpha$=$\alpha$p-($\alpha$p-$\alpha$o) exp(-kㆍLAI) where $\alpha$p was the reflectance at the maximum LAI and $\alpha$o was that of the bare soil. The ap ranged from 0.025 to 0.035 and $\alpha$o ranged from 0.11 to 0.12, respectively. The reflected PAR ranged from 0.049 to 0.064 and the transmitted PAR ranged from 0.168 to 0.340 until maximum dry weights were observed. The slope from the linear regression of dry matter on absorbed PAR, conversion efficiency, ranged from 1.30 to 2.3g MJ$^{-1}$ during the growing season until maximum dry weight was reached. The total dry matter yield above ground (TDM) increased with the increases in the conversion efficiency. TDM was higher in Hwanggeumkong than Paldalkong and higher in the space of 30$\times$15cm than 60$\times$15cm, Paldalkong showed higher harvest index than Hwanggeumkong. than Hwanggeumkong.

• Journal of Korean Society for Quality Management
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• v.40 no.3
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• pp.359-371
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• 2012

Purpose: Due to the explosive growth and widespread use of smartphones, new business opportunities are emerging. Despite the importance of creating customer value in using smartphone applications, past studies on have mainly focused on functions or factors and specifications that influence users to use the device. Methods: This study is intended to identify how customer dissatisfaction from the use of smartphone application services affects customer sentiment and behavior. The research model is tested via a survey of 290 smartphone application users. Results: The result of this empirical study indicates that customer dissatisfaction significantly affects the user's disappointment and regret in using a service, which are subordinate values of customer emotion. The user's anger is positively associated with 'Negative word of mouth' and 'Complaint', which are subordinate values of customer behavior, but not with an intention to switch to another service. 'Regret' and 'Disappointment' are positively associated with 'Negative word of mouth' and 'Switching intention', but not with 'Making direct complaints'. Finally, customer's negative sentiments are a significant intermediary in the relationship between customer dissatisfaction and behavioral response. Conclusion: Finally, the study offers a more systematic understanding on the phasal response process of customer dissatisfaction in relation to the provision of smartphone application services.

• Journal of Technology Innovation
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• v.21 no.1
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• pp.1-26
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• 2013

The objectives of this paper are to analyze the effect of government R&D expenditure on employment in the Korean manufacturing sector in which employment is rapidly declining. According to the results of our empirical analysis, government R&D expenditure decreases the level of employment in Korean manufacturing sector in short term period, but it has positive effect on employment by compensation effect in the middle and long term period. Second, the effect of private R&D expenditure on job creation is three times larger than that of government R&D expenditure. Third, costs of labor and capital has negative effect on employment. This study is believed to help understanding the relation between R&D expenditure and employment, and providing policy implications of how to plan and manage government R&D expenditure as a tool of job creation.

• Korean Journal of Child Studies
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• v.4
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• pp.23-35
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• 1983

The purpose of this study is to systematize the theory of the father-child relationship by analyzing the father's role and father-child interaction. The results of this study are as followings: (1) The oedipal period 3 to 5 years is a critical in development of the father-child relationship. Father absence is assumed in infancy but it is denying because the father participates in Child- rearing activity. (2) The Father's role is symbolized instrumental role traditionally and culturally but it is appropriate that we think the father's role to be androgynous concepts. Instrumental role as well as expressive role is expected to father's role. (3) The role of the father is supplementary mother's role. The father provides economic, emotional support and helps the balanced child- rearing. This indirect role of the father is very important. (4) The father influences child development, and his role is to be sex-role model to contrieve personality internalize moral development. But it is needed more empirical study to clarify father's effects on child development. (5) The amount of time that fathers spend with their children is less than mothers, but it is not assumed that difference of this amount of time do not differently influence to the children. (6) There are much similarity that difference between father-child interaction and mother- child interaction. Qualitative difference in interaction is response style. A responsive style of the father is physical intellectual instructive but mother's is verbal. (7) The effects of the father to a child must be analyzed on dyadic dimension and triadic dimension of family network. In triadic dimension, father influences mother- child relationship, mother to response sensitively, husband-wife relation.

• The Journal of the Korean dental association
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• v.54 no.12
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• pp.971-984
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• 2016

The increase rate of dentists' competition is very fast at metropolitan areas in South Korea. We compare metropolitan and rural parameters to investigate the relation between competition and revenue variation. The competition and revenue variables of 73 metropolitan and 75 rural areas were calculated from 2010 Census of Service Industry microdata which include non-insurance revenues of dental clinics. Independent sample t-test results showed that the level of competition among dental clinics in metropolitan areas is higher. The lowest and the low ranked revenues are higher in rural areas. The highest and the average revenues are higher in metropolitan areas. But, 25 percentile and median revenues has no significant difference between two areas. Simple log linear regression results showed that the number of clinics could explain the distribution of revenues in both areas better than the density of active dentists and Herfindahl-Hirschman index. In the areas with many clinics have high maximum and average revenues and low minimum revenues. The increasing rate of maximum revenues is higher in metropolitan areas though the decreasing rate of minimum revenues is higher in rural areas. Metropolitan areas have higher Gini coefficients than rural areas, but the increasing rate of Gini coefficients is lower than rural areas. Findings from this study are useful reference when the dentists select the opening areas. One is that the median revenues between metropolitan and rural areas have no significant difference. The other is that the rural areas ensure the more stable and uniform revenues. The results would help to relieve the consumptive competition among dentists and to achieve the distributional efficiency of dental human resources.

• Journal of the Korean Society of Costume
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• v.23
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• pp.197-209
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• 1994

The purpose of this study is to present a way to analyze and review the subjective view of the aesthetic for dress based on the framework of the aesthetic categories suggested by aesthetics. In order to define objectivism and subjectivism of the aesthetic of dress, theoretical studies on the aesthetic categories of dress were precded. And empirical studies on the aethetic categories of dress for selected period, the Renaissance (16th century) and the Baroque(17 th century). The results were follows : The objectivism of the aesthetic is the point of that an object causes human to feel and judge aesthetically, that is that of dress means judge aesthetically, that is that of dress means formal characteristic of dress and pervasive ideology expressed in dress. the subjectivism of the aesthetic is the point that the aesthetic is ruted in human, that is that of dress has been studied in relation to the image, the aesthetic consciousness m, or the aesthetic categories of dress. Especially, the aesthetic category is one of the universal and valid methods for the analysis of subjectivism of the aesthetic for dress. This study includes beauty, grace, elegance , the sublime, the tragic , the comic, aptness, ugliness as aesthetic categories of dress . Beauty is perfection and rule. Grace pleases human by sense. Elegance comes from the harmony of sense and spirit. the sublime comes into existence that human feels pleasure as well as displeasure simultaneously when human is overehelmed by objects. The tragic is the sense of the present of something valuable even if there is suffering. The comic is the sense of the presence of something amusing even if there is displeasure caused by contradiction. Apteness means utility in terms of the objectivism and , formality in terms of the subejctivism. Ugliness is opposite to beauty. As the result of emperical studies, the aesthetic categories of the Renaissance dress showed harmonious, balanced, and symmetrical beauty, and the magnificent, and enlarged sublime. In addition to these , grace and elegance were also found to some extent. Aesthetic categories of the Baroque dress show feminie, soft, cheerful, and fantastic grace, asymmetric , disarmonious, and extraordinary uglinesss, and the magnificient , grave, and dignified sublime.

• Journal of the Korean School Mathematics Society
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• v.15 no.2
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• pp.331-348
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• 2012

With a gradual increase in research on teaching and learning calculus, there have been various studies about students' thinking about the derivative. This paper reviews the results of the existing empirical studies published in Korean and English. These studies mainly have shown that how students think about the derivative is related to their understanding of the related concepts and the representations of the derivative. There are also recent studies that emphasize the importance of how students learn the derivative including different applications of the derivative in different disciplines. However, the current literature rarely addressed how students think about the derivative in terms of the language differences, e.g., in Korean and English. The different terms for the derivative at a point and the derivative of a function, which shows the relation between concepts, may be closely related to students' thinking of the derivative as a function. Future study on this topic may expand our understanding on the role language-specific terms play in students' learning of mathematical concepts.

• Computers and Concrete
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• v.22 no.5
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• pp.481-492
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• 2018

In this paper, a new hybrid fiber system (NHFS) is investigated for the application of slab. The steel fiber, polyvinyl alcohol (PVA) fiber and calcium carbonate ($CaCO_3$) whisker is added to form NHFS. The four-point bending test is carried out on the flexural properties of slab with plain, steel fiber, traditional hybrid fiber system (THFS) and NHFS reinforced cementitious composites. The flexural behavior is evaluated by ASTM C1018-97, JCI-SF4 and post-crack strength (PCS) technique. The evaluation parameters of flexural toughness such as toughness index (TI), equivalent flexural strength (EFS) and PCS are determined. The size of slab specimens is $15mm(thickness){\times}50mm(width){\times}200mm(length)$. The results show that adding $CaCO_3$ whisker to THFS can significantly improve the flexural strength, TI, EFS, PCS of the slab. The empirical relation between reinforcing index ($RI_v$) and flexural parameters show that flexural parameters of slabs increase first and then decrease; which indicates that optimum $RI_v$ values can be helpful in the considering the mix design of steel-PVA fibers-$CaCO_3$ whisker composites for achieving the desired flexural-related properties. The scanning electron microscopy is performed to observe the micro-morphological characteristics of the fracture surface, which proved the positive hybrid effect among the different fibers in cementitious composites. The NHFS can arrest the generation and propagation of the crack from micro to macro level.

• Atmosphere
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• v.27 no.1
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• pp.55-65
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• 2017

This study investigates how Eurasian snow cover in spring (March and April) is associated with Korean temperature during summer (June-July-August). Two leading modes of Eurasian snow cover variability in spring for 1979~2015 are obtained by Empirical Orthogonal Function (EOF) analysis. The first EOF mode of Eurasian snow cover is characterized by a zonally elongated pattern over the whole Eurasian region and its principal component is more correlated with Korean temperature during June. On the other hand, the second EOF mode of Eurasian snow cover is characterized by an east-west dipole-like pattern, showing positive anomalies over eastern Eurasian region and negative anomalies over western Eurasian region. This dipole-like pattern is related with Korean temperature during August. The first leading mode of Eurasian snow cover is associated with anomalous high (low) pressure over Korea (Sea of Okhotsk) during June, which might be induced by much evaporation of soil moisture in Eurasia during March. On the other hand, the second mode of Eurasian snow cover is associated with a wave train resembling with Eurasian (EU)-like pattern in relation to the Atlantic sea surface temperature forcing, leading to the anomalous high pressure over Korea during August. Understanding these two leading modes of snow cover in Eurasian continent in spring may contribute to predict Korean summer temperature.