• Korean Journal of Mathematics
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• v.16 no.3
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• pp.369-378
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• 2008

The aim of this paper is to study the stability problem for the pexider type trigonometric functional equation f(x + y) − f(x−y) = 2g(x)h(y), which is related to the d'Alembert, the Wilson, the sine, and the mixed trigonometric functional equations.

• Macromolecular Research
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• v.17 no.2
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• pp.110-115
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• 2009

The electrical, morphological and rheological properties of melt and dry mixed composites of poly ethylene (PE)/graphite (Gr), polypropylene (PP)/Gr and PP/nickel-coated carbon fiber (NCCF) were investigated as a function of filler type, filler content and processing temperature. The electrical conductivities of dry mixed PP/NCCF composites were increased with decreasing processing temperature. For the melt mixed PP/NCCF composites, the electrical conductivities were higher than those of the melt mixed PE/Gr and PP/Gr composites, which was attributed to the effect of the higher NCCF aspect ratio in allowing the composites to form a more conductive network in the polymer matrix than the graphite does. From the results of morphological studies, the fillers in the dry mixed PP/NCCF composites were more randomly dispersed compared to those in the melt mixed PP/NCCF composites. The increased electrical conductivities of the dry mixed composites were attributed to the more random dispersion of NCCF compared to that of the melt mixed PP/NCCF composites. The complex viscosities of the PP/Gr composites were higher than those of the PP/NCCF composites, which was attributed to the larger diameter of the graphite particles than that of the NCCF. Furthermore, the fiber orientation in the 'along the flow' direction during melt mixing was attributed to the decreased complex viscosities of the melt mixed PP/NCCF composites compared those of the melt mixed PP/Gr composites.

• Korean Journal of Environmental Agriculture
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• v.37 no.3
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• pp.160-165
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• 2018

BACKGROUND: Mixed cropping of legume and grass was effective system in view point of providing organic matter and nitrogen or reducing the nitrogen starvation of following crop. The relation of the change of N and P constituents depending on the cropping types and those effects on the growth and nutrient uptake of the following crop were observed. METHODS AND RESULTS: Three cropping types, hairy vetch mono cropping, barley mono cropping, and mixed cropping of hairy vetch and barley were applied. Soil properties, growth characteristics, and nitrogen production of green manure crops were observed. In additions, the effect of cropping types on the growth pattern of corn as the following crop was observed. In the mixed cropping system, creeping type hairy vetch climbed to the erect type barely for light utilization resulting in improvement of light interception rate and higher LAI (Leaf Area Index) than in mono cropping. Mixed cropping showed higher biomass production and soil nitrogen availability among the cropping types, indicating relatively much more nutrient supply and higher yield production of following crop. CONCLUSION: Mixed cropping showed relatively higher LAI (dry matter) mainly because of intense competition for light utilization usually after flowering stage. Mixed cropping also showed relatively higher yield of corn, the following crop rather than other types, mainly due to the more biomass production potential and higher N and P production ability. Therefore, mixed cropping was adaptable method to reduce or replace chemical fertilizer application for environmentally-friendly agriculture.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.75-84
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• 2017

In recent years, several interesting families of generating functions for various classes of hypergeometric functions were investigated systematically. In the present paper, we introduce a new family of extended Wright type hypergeometric function and obtain several classes of generating relations for this extended Wright type hypergeometric function.

• Journal of Navigation and Port Research
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• v.38 no.5
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• pp.527-539
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• 2014

This study establishes the research model and sets up the hypothesis in order to analyze the effect of the type of mixed manning and the ratio of foreign crew on the group cohesiveness, job satisfaction and organizational commitment in ship organizations and the moderating effect of the acceptance and adaptation of cross-culture. For statistical hypothesis testing, it conducts a questionnaire survey targeting mixed manning ships and examines empirically the inter-variables relation through the regression. The result of empirical research is that the group cohesiveness, job satisfaction and organizational commitment in the ship organization of Korean master(chief engineer) and foreign officers is higher than that of Korean master and officers. Moreover, it is found that the group cohesiveness of 31~50% foreign crew group is less than that of the others. However, There is no moderating effects of the acceptance and adaptation of cross-culture. Additionally, it demonstrates the higher job satisfaction and organizational commitment in the stronger cohesiveness groups. The finding suggests the rationale that shipping and ship management companies could raise the group cohesiveness, job satisfaction and organizational commitment by moderating the type of mixed manning and the ratio of foreign crew.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3265-3276
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• 1996

The studies of document recongnition have been focused mainly on Korean documents. But most of documents composed of Korean and other characters. So, in this paper, we propose the document recognition system that can recognize the multi-size, multi font and mixed type characters. We have utilized a large scale network model, "CombNET" which consists of a 4 layered network with combstructure. And we propose recognition method that can recognize characters without discrimination of character type. The first layer constitutes a Kohonen's SOFM network which quantizes an input feature vector space into several sub-spaces and the following 2-4 layers constitutes BP network modules which classify input data in each sub-space into specified catagories. An experimental result demonstrated the usefulness of this approach with the recognition rates of 95.6% for the training data. For the mixed type character documents we obtained the recognition rates of 92.6% and recognition speed of 10.3 characters per second.

• Journal of Preventive Medicine and Public Health
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• v.24 no.3 s.35
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• pp.314-327
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• 1991

To evaluate the effects on health by exposure to mixed organic solvents, the author analyzed some labortory findings of blood (hemoglobin, hematocrit RBC, WBC, SGOT, SGPT) and urine (protein, blood, sugar) that were obtained from 722 workers (male:446, female:276) who worked in plywood, painting and shoes factories in Pusan area from January to December, 1990. The result were as follows ; 1. The mean values of each hematologic findings were all within normal limit but there were significant differences at hematocrit, RBC, WBC, SGOT in male and at WBC, SGPT in female at the comparison of the mean values and the distribution according to the normal criteria by type of work. 2. There were no differences in urinalysis(protein, blood, sugar) by type of work. 3. In stepwise multiple regression, analysis of hematologic findings on age, working duration and type of work, regression coefficients on age and type of work were relatively high in male and female sub1, respectively. As a result of this study, it is considered that the measurement of WBC with morphology is significant in hematologic findings and instead of spot urine and urinstix, 24 hours urine and quantitative analysis is required in urinalysis in screening test for healthy status of workers who deal with the organic solvents.

• The Korean Journal of Applied Statistics
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• v.23 no.5
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• pp.891-908
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• 2010

In Korea, the small area estimation method is currently unpopular in generating o cial statistics. Because it may be difficult to determine the reliability for small area estimation, although small area estimation ha a sufficiently good advantage to generate small area statistics for Korea. This paper inspects the method of making small area unemployment through the small area estimation method. To estimate small area unemployment we used an EBLUP-type estimator based on a logistic linear mixed model. To evaluate the EBLUP-type estimator we accomplished the real data analysis and simulation experiment from the population and housing census data. In addition, small area estimates are compared to large sample survey estimates. We found the provided method in this paper is highly recommendable to generate small area unemployment as the official statistics.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.542-546
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• 2009

Methane production using the mixed organic wastes of peel-type fruit wastes from apple or orange and sewage sludge was investigated in the batch anaerobic degradation process. When apple or orange peels with sewage sludge were used as mixed substrates, higher methane production was achieved under the condition of 3 : 7 (fruit peel : sewage sludge) mixing ratio. However, above the 3 : 7 mixing ratio, the pH of mixture was decreased from 8.0 to 4.5~4.7 due to organic acid production from the fruit wastes. Subsequently, methane production was low. The results in this study could be effectively applied to the methane gas production system as a bioenergy in the mixed batch anaerobic digestion process using the peel-type fruit wastes and sewage sludge.

• Journal of Animal Environmental Science
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• v.5 no.1
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• pp.53-62
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• 1999

This study was carried out to investigate how to reuse the livestock waste and develop fly ash as a subsitution of sawdust which is used commonly to make compost. Fly ash and sawdust were mixed the ratio of 8 to 2, 7 to 3, 6, to 4, 5 to 5, 4 to 6. 3 to 7 and 2 to 8 after fermentation for 60 days the change of temperature, moisture, pH, organic matter, nitrogen content and C/N ratio were analyzed. The results are as follows; Temperature was reached to maximum (63.5$^{\circ}C$) more quickly in scraper type than in slurry type with adding large sawdust. When fly ash and sawdust were mixed same amount at scraper type and slurry type, moisture was 46.6~53.7% and maintained a good condition for fermentation. pH was showed the range of 7~10 as a mixture of fly ash. Organic matter contents were increased with increasing the added sawdust but did not show any tendency. Nitrogen content was also increased with increasing the amount of added sawdust but did not show any tendency. C/N ratio was increased to 20~60 with increasing the added sawdust, but when sawdust and fly ash were mixed 50:50, there was no significant during fermentation periods. In conclusion, supplementation of fly ash at the level of 50% of sawdust maintained a good condition for fermentation as a livestock waste composting.