• Journal of Korea Trade
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• v.23 no.4
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• pp.30-57
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• 2019

Purpose - This study analyzes the effect of internationalization represented as exporting on firm performance on the subject of SMEs operating in Masan Free Trade Zone which has shown poor performance recently despite its status as the oldest and largest free trade zone in Korea. We also analyze the effect of firm size on firm performance, and the moderating role of firm size in relation to internationalization and firm performance. Design/methodology - This study uses multiple regression models for unbalanced panel data as the empirical tools for the estimation of the effect that internationalization has on firm performance (ROA or ROS). Our sample consists of 91 manufacturing SMEs among all 110 companies located in Masan Free Trade Zone as of 2017. Findings - The degree of internationalization has a negative impact on firm performance. However, firm size turns out to have a positive effect and play a positive moderating role in the relation to internationalization and firm performance. This seems to be because most tenant companies operating in Masan Free Trade Zone are small firms whose costs of internationalization may exceed the benefits. Empirical results also show that longer CEO tenure has a greater negative effect on firm performance. Originality/value - The originality/value of this paper can be found in 3 aspects. First, we conducted an empirical analysis on the relationship between the internationalization and firm performance of SMEs in a specific region, namely, Masan Free Trade Zone. Second, while most previous studies focused on listed medium companies, most of the sample of this study are small and medium non-listed enterprises. Third, it is witnessed that firm size has a positive moderating effect on the relation between internationalization and firm performance.

• Journal of Bio-Environment Control
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• v.15 no.4
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• pp.340-345
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• 2006

A potato (Solanum tuberosum L. cv. Superior) cultivar was grown in aeroponic cultivation system to investigate the effect of root zone cooling in summer. Based on their nutrient uptake, growth responses, and tuberization, the possibilities for potato seed production were determined. Although shoot growth and early tuberization increased in the conventional non-cooling root zone system (root zone temperature of $25\pm2^{\circ}C$), stolen growth, photosynthesis, transpiration rate and number of tubers produced were higher in the cooling root zone system ($20\pm2^{\circ}C$) than in the non-cooling system. Increasing root zone temperature above $25^{\circ}C$ stimulated absorption of K more than T-N, P, Ca, Fe and Mn. On the other hand, root zone temperatures in the range of $20^{\circ}C$ to $25^{\circ}C$ did not affect Mg contents. The lower uptake and supply to leaves of T-N, Fe and Mn at the high root zone temperature promoted early tuberization and advanced haulm senescence. The results stress the importance of keeping root zone temperature to as low as below 20, particularly in summer under temperate Bone.

• East Asian mathematical journal
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• v.34 no.4
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• pp.339-358
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• 2018

There has been researches for effective education. Among them, many researchers are striving to apply Zone of Proximal Development of Vygotsky which is emphasizing the social interaction in the field of teaching and learning. Researchers usually research based on individual or small group of students. However the math class in school relies on system that one teacher teach many students in reality. So this research will look for the effect that the teaching and learning program based on Zone of Proximal Development of Vygotsky by designing the teaching and learning program which is based on scaffolding structuring to overcome the zone of proximal development in many-students class. The results of this research are as follows: First, the studying program considered the theory of Vygotsky has a positive effect on improving the mathematical achievement of elementary student. Second, the studying program considered the theory of Vygotsky has a positive effect on improving the student's studying attitude upon mathematics.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.85-89
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• 2002

This paper used the Laser Speckle Interferometry to present the strain analysis of Nd:YAG Laser welding zone. Previous TIG welding to sheet plate, which welds only high-skilled engineer, produces residual stress nearby welding zone due to thermal effect. However, Laser welding makes sheet pate welding easy and thermal effect minimum. Thermal effect zone is measured by strain analysis of the laser-welding zone by ESPI under tensile testing of sheet plate welded by Nd:YAG laser. The ESPI results, which compared with strain gage method, are agreed within error 3 %.

• International Area Studies Review
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• v.14 no.1
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• pp.203-219
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• 2010

Nowadays an instability of the exchange rate on accounts of global finance crisis brings on a lot of an economic damage such as recession, decreasing of total trade and so on. However some countries which belong to be membership of the eurozone could escape economic slump shortly and easier than others. The reason for this is that they share with the Euro as a their own currency which is the second vehicle currency all of the world. This paper analyzes the correlation of joining the Euro zone and trade with pooled OLS, random effect estimation, and fixed effect estimation. A membership of the Euro zone are able to increase trade 11.3% ~ 25.3% one another on average since some country belongs to the Euro zone. It is very important for some countries which have a plan to affiliate the Euro zone sooner or later to realize economic effect because of a protection of the Euro zone as well as political power.

• Journal of the Korean Society of Combustion
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• v.12 no.3
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• pp.24-32
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• 2007

A theoretical model was developed for rotary kiln and computational study was conducted to find the effect of feeding characteristics. One dimensional model with the variations of heating distribution, length of heating zone, excess air ratio and revolution was considered. The comparison of parallel-flow rotary kiln with that of counter-flow was conducted. For parallel-flow type, it is found that the variation of temperature of solid is not great for the zone that is following flame-heating zone. This zone is good to take the special treatment because thermal deviation is small and contacting time is enough for another treatment. Increase of excess air ratio have the effect of decreasing solid temperature. But this effect of decreasing solid temperature goes small for the great excess air ratio. The heating is efficient for the flame which has the maximum heating at the central region of the full length.

• Geomechanics and Engineering
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• v.8 no.6
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• pp.783-799
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• 2015

In this study, effect of horizontal in situ stress on failure mechanism around underground openings excavated in isotropic, elastic rock zones is investigated. For estimating the plastic zone occurrence, an induced stress influence area approach (Bray Equations) was modified to define critical stress ratio according to the Mohr-Coulomb failure criterion. Results obtained from modified calculations were compared with results of some other analytical solutions for plastic zone thickness estimation and the numerical modelling (finite difference method software, FLAC2D) study. Plastic zone and its geometry around tunnels were analyzed for different in situ stress conditions. The modified equations gave similar results with those obtained from the other approaches. However, safer results were calculated using the modified equations for high in situ stress conditions and excessive ratio of horizontal to vertical in situ stresses. As the outcome of this study, the modified equations are suggested to use for estimating the plastic zone occurrence and its thickness around the tunnels with circular cross-section.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.129-134
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• 2003

It is very important to pay careful attention to construction of bridge/earthwork transition zone for high-speed railway. The transition zone of the railway is the section which roadbed stiffness is suddenly varied. Differences in stiffness have dynamic effects and these increase the forces in the track and the extent of deformation. An abrupt change of stiffness across two adjacent track portions cause irregular settlement of roadbed, track irregularity, lack of girder bending moment and reduction of lateral resistance. Especially on high-speed railway, track irregularity of transition zone cause sincere effect to track stability and train safety. And so continuous maintenance is needed. To verify this effect and to improve transiton zone capacity, In situ test, track irregularity and train acceleration test were performed on high-speed railway bridge/earthwork Transiton Zone.

• Nuclear Engineering and Technology
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• v.42 no.5
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• pp.562-567
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• 2010

A One-Dimensional Water Flow and Contaminant Transport in Unsaturated Zone (FTUNS) code has been developed in order to interpret radionuclide migration in an unsaturated zone. The pore-size distribution index (n) and the inverse of the air-entry value ($\alpha$) for an unsaturated zone were measured by KS M ISO 11275 method. The hydraulic parameters of the unsaturated soil are investigated by using soil from around a nuclear facility in Korea. The effect of hydraulic parameters on radionuclide migration in an unsaturated zone has been analyzed. The higher the value of the n-factor, the more the cobalt concentration was condensed. The larger the value of $\alpha$-factor, the faster the migration of cobalt was and the more aggregative the cobalt concentration was. Also, it was found that an effect on contaminant migration due to the pore-size distribution index (n) and the inverse of the air-entry value ($\alpha$) was minute. Meanwhile, migrations of cobalt and cesium are in inverse proportion to the Freundich isotherm coefficient. That is to say, the migration velocity of cobalt was about 8.35 times that of cesium. It was conclusively demonstrated that the Freundich isotherm coefficient was the most important factor for contaminant migration.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1389-1394
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• 2003

$CO_2$ is a well-known green house gas, which is the major source of global warming. Many researchers have studied to reduce $CO_2$ emission in combustion processes. Among the method for reducing $CO_2$ emission, oxygen-enriched combustion has been proposed. But the adiabatic flame temperature is too high. So existing facilities must be changed, or the adiabatic flame temperature in the combustion zone should be reduced. The combustion characteristics, composition in the flame zone, temperature profile and emission gases were studied experimentally for the various oxygen-enriched mtios(OER) by addition of $CO_2$ under coustant $O_2$ flowrate. Results showed that the reaction zone was quenched, broadened, as addition of $CO_2$ was increased. Temperature has a large effect on the NOx emission. The emission of NOx in flue gas decreased due to the decreased temperature of reaction zone. It was also shown that the reaction was delayed by the cooling effect. As the addition of $CO_2$ was increased, the composition of CO in the flame zone increased due to the increase of reaction rate by increasing mixing effect of oxidant/fuel at OER=0, but the composition of CO decreased by quenching effect at OER=50 and 100%.