• 한국안전학회지
• /
• 제28권1호
• /
• pp.47-51
• /
• 2013

This research is the descriptive survey research targeting construction workers for searching a vitalization method on safety education by understanding the real condition of the sense of safety consciousness and the condition of safety education. The collected data of 147 workers are analyzed by using arithmetic mean, t-test, and ANOVA Analysis of Variance through SPSS PC program. This research investigated the real condition of safety consciousness, recognition on safety education, and the differences of safety consciousness depend on the general characteristic of subject. According to the result of the study, development of standardized safety consciousness assessment tool and institutionalization of safety education program is needed.

• 정보학연구
• /
• 제2권1호
• /
• pp.191-207
• /
• 1999

본 연구는 고객만족모형의 선정에 있어 재구매 의사와 예측타당성을 체계적으로 검토하려는 시도이다. 일반적으로 고객만족의 측정을 위해서는 단일항목척도와 복수항목척도를 사용하고 있다. 그러나 고객이 제품특성을 잘 모르는 경우는 이용하는 모형이나 측정방법에 따라 계산된 지수의 신뢰성이나 구매의도와의 상관관계는 높지 않는 경우가 발생한다. 이러한 문제의 해결을 위하여 본 연구에서는 통상적으로 활용되는 고객만족지수의 다양한 측정방법들에 대해 예측타당성을 검토하여 적절한 모형을 찾아내려는 시도이다.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
• /
• pp.367-373
• /
• 2001

The effect of characteristic of surface roughness and roughness patterns on friction and sliding wear was studied experimentally under reciprocating boundary lubricant sliding conditions. The test was conducted with specimens which have various arithmetic mean value and roughness pattern under the condition of different normal load. The experimental results show that the friction coefficient is decreased because of oxidation mass and valley effect as the normal loads increasing It was found that the specimens with surface roughness with a transverally oriented pattern have a smaller firction coefficient than the other two roughness patterns under the condition of the roughness values of Ra=0.5 and Ra=0.2 .

• 한국수학사학회지
• /
• 제27권6호
• /
• pp.409-419
• /
• 2014

In school mathematics, the logarithmic function is defined as the inverse function of an exponential function. And the natural logarithm is defined by the integral of the fractional function 1/x. But historically, Napier had already used the concept of logarithm in 1614 before the use of exponential function or integral. The calculation of the logarithm was a hard work. So mathematicians with arithmetic ability made the tables of values of logarithms and people used the tables for the estimation of data. In this paper, we first take a look at the mathematicians and mathematical principles related to the appearance and the developments of the logarithmic tables. And then we deal with the confusions between mathematicians, raised by the estimation data which were known as proportional parts or mean differences in common logarithmic tables.

• Food Science and Biotechnology
• /
• 제27권6호
• /
• pp.1755-1760
• /
• 2018

The objective of this study was to perform genetic diversity analysis of 13 strains isolated from South Korean foods by multilocus sequence typing (MLST). For typing, seven housekeeping loci (atpA, dnaA, dnaK, gyrB, pheS, pyrG, and rpoA) were selected, amplified and analyzed. Fifty-one polymorphic sites varying from 1 to 22 in each species were identified. Thirteen sequence types were generated with allele numbers ranged from 2 to 10. The overall relationship between strains was assessed by unweighted pair group method with arithmetic mean dendrogram and minimum spanning tree. In addition, combined spits tree analysis revealed intragenic recombination. No clear relationship was observed between the isolation sources and strains. The developed MLST scheme enhanced our knowledge of the population diversity of Leu. citreum strains and will be used further for the selection of industrially important strain.

• 동력기계공학회지
• /
• 제22권6호
• /
• pp.44-50
• /
• 2018

As a type of bolt with a spherical head, the ball stud is widely used as a part of a ball joint in steering or suspension systems in automobiles. Balls and studs are subjected to heat treatment suitable for each material; in particular, the shear strength of the ball stud must meet the specifications of the production company. This study evaluated the shear strength of joints according to the cooling method of ball studs subject to resistance welding. The shear stress of water cooling was higher than that of air cooling (as-received material). Note, however, th at oil cooling showed lower stress than that of as-received. When judged by standard deviation, mean, and coefficient of variation according to the arithmetic statistics and shape parameter as well as scale parameter, oil cooling is suitable.

• 한국육종학회지
• /
• 제42권1호
• /
• pp.28-34
• /
• 2010

Diversity of 30 Korean potato cultivars was evaluated using 14 microsatellite markers. Twelve microsatellite markers representing 12 loci in the potato genome detected 84 polymorphisms among 30 cultivars and revealed alleles with a mean of 7.00 alleles per primer. The polymorphism information content (PIC) value ranged from 0.57 to 0.93 with average of 0.82. Based on polymorphism, cluster analysis was conducted by the unweighted pair-group method with arithmetic average (UPGMA) methods. Thirty potato varieties were distinctly separated into 2 groups and similarity coefficient of cluster ranged from 0.58 to 0.95. Thirty tetraploid cultivars were evaluated for six important agronomic traits. One-way analysis of variance was done to look for the degree of relationships between individual markers and traits. K1 and K2 markers showed a significant association with amylose contents, starch contents, and specific gravity.

• 한국정밀공학회지
• /
• 제12권12호
• /
• pp.149-156
• /
• 1995

This paper presents the surface profile of machined workpiece in face milling operation. The roughness model of feed direction is considered the cutting condition, the profile and run-out of inserts. For the dynamic model the cutting system can be modeled as avibratory system. The dynamic model of surface roughness is considered the relative displacements between tool and work- piece which can be obtained from the cutting system. These model can predict various surface roughnesses. i.e. maximum and arithmetic mean surface ruughnesses. Therefore, the developed model can be used for the monitoring of surface roughness.

• Journal of applied mathematics & informatics
• /
• 제41권6호
• /
• pp.1181-1191
• /
• 2023

This paper investigates Young inequalities for matrices, a problem closely linked to operator theory, mathematical physics, and the arithmetic-geometric mean inequality. By obtaining new inequalities for unitarily invariant norms, we aim to derive a fresh Young inequality specifically designed for matrices.To lay the foundation for our study, we provide an overview of basic notation related to matrices. Additionally, we review previous advancements made by researchers in the field, focusing on Young improvements.Building upon this existing knowledge, we present several new enhancements of the classical Young inequality for nonnegative real numbers. Furthermore, we establish a matrix version of these improvements, tailored to the specific characteristics of matrices. Through our research, we contribute to a deeper understanding of Young inequalities in the context of matrices.

• 한국분무공학회지
• /
• 제13권3호
• /
• pp.134-142
• /
• 2008

In the case of heavy duty diesel engines, the Urea-SCR system is currently considered to reduce the NOx emission as a proved technology, and it is widely studied to get the high performance and durability. However, the nozzles to inject the urea-water solution into the exhaust pipe occur some problems, including the nozzle clogging, deposition of urea-water solution on the inner wall of the exhaust pipe, resulting in the production of urea salt. In this study, a swirl-type twin-fluid nozzle to produce more fine droplets was used as a method to solve the problems. The effect of the nozzle cap geometry, including the length to diameter ratio ($l_o/d_o$) and chamfer, on the spray characteristics were investigated experimentally. The length to diameter ratio of nozzle cap were varied from 0.25 to 1.125. The chamfer angle of the nozzle cap was constant at 90o. The mean velocity and droplet size distributions of the spray were measured using a 2-D PDA (phase Doppler analyzer) system, and the spray half-width, AMD (arithmetic mean diameter) and SMD (Sauter mean diameter) were analyzed. At result, The larger length to diameter ratio of nozzle cap were more small SMD and AMD. The effect of the chamfer did increase the radial velocity, while it did not affect the atomization effect.