• Journal of Advanced Marine Engineering and Technology
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• v.33 no.8
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• pp.1152-1161
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• 2009

The power measurement of main propulsion system on the new vessels can be classified with the direct method acquired from the shaft's strain using strain gauge and the indirect method converted and summed from all of cylinders combustion pressure using mechanical or electrical pickup device during the sea trial. This power is fluctuated by external factors which was influenced by various sea motions with long time interval and by internal factors which was influenced by varying torques of torsional vibration and bending moment, due to mis-aligned shaft and whirling vibration with short time interval. In this paper, the statistical analysis method for the shaft power measurement and assessment using strain gauge in marine vessels are introduced. And these are identified by the low speed two stroke diesel engine model and four stroke medium speed diesel engine model including reduction gear.

• Journal of Conservation Science
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• v.31 no.3
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• pp.267-278
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• 2015

In this study, the elastomer cover, a new contact material, was developed to establish the customized ultrasonic measurement considering surface irregularities of stone cultural heritages. The cover exhibits high elastic force and wear resistance because it has tensile strength of 17MPa and elongation of 625%. In addition, as a result of comparative experiments for the seven types according to transducers and contact materials including the elastomer cover, rock surface irregularities significantly affect attenuation of ultrasonic velocity. The phenomenon was more noticeable in the chiseling finish and indirect transmission measurement rather than the dabbed finish and direct transmission measurement. However, the Type F using the exponential transducer and elastomer cover showed stable P-wave velocity and high amplitude regardless of the surface irregularities. This because the elastomer cover sufficiently sticks to surface irregularities and removes pores between a transducer and a rock specimen. Therefore, the Type F should be used for the ultrasonic measurement of stone cultural heritages with surface irregularities.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.271-279
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• 2015

The purpose of this research is to verify the impact of job stress on turn over intention among the married workers in small and medium sized enterprises in South Korea, as well as to examine mediation effect of work-family conflict between the two variables. For this research, 135 workers were selected through a web-based survey from February to March, 2015. As results, job stress was statistically influential on turnover intention and work-family conflict. Work-family conflict implied the partial mediation effect of turnover intention, with both direct and indirect impacts on depression. The findings suggest that preventive programs against job stress and work-family conflict, such as Employee Assistance Programs(EAPs), should be launched in order to reduce the problems. Korean government must legislate for family-friendly work environment to help company could activate the assistance programs for the employees who suffer from the work-family conflicts.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.12
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• pp.677-684
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• 2016

For realistic rendering volume to calculate the light effects as well as the shade is essential. In order to produce the high quality of the resulting image, it is necessary to represent a global illumination, and it should be considered an indirect effect of the direct impact and scattering of light. It requires a lot of resources in order to perform this operation and, in particular, is very expensive when large amounts of data to be rendered as a volume data is consumed. In this paper, we generate a scatterer template according to the physical laws for each material. Considering that each object having material property stores photons of the template based on the Lambert illumination model. When the volume rendering in this paper, using the photon is stored in the template, based on the voxel to be sampled within the examination volume occluded, and it represents the global illumination of the scattering. Because the materials produced by the template requires a less resource only if comprised of a complex material, a simple operation can be expressed within the scattering volume at a low cost through.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.195-207
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• 2020

In Korea, specific thermal elements such as annual mean temperature (AMT) 13℃, 14℃, and Kira's coldness index (CI) -10℃, have been suggested about the northernmost distribution of the warm-temperate evergreen broad-leaved forest zone. We reviewed the relationship between three thermal elements and the actual distribution of evergreen broad-leaved woody plants or its communities. Thiessen and Kriging method using point-data calibrated by seasonal lapse rate according to altitude were utilized for the spatial distribution pattern analysis. Several phytoclimatic maps were also produced in order to compare different thermal values. We identified that the AMT 13℃ was the best thermal element to demarcate the northern limit of the warm-temperate forest zone. Its area was estimated ca. 20,334 ㎢ and larger than those of other thermal elements. We concluded that an indirectly fabricated index i.e. CI -10℃ is useless and it was enough for a direct value of AMT 13℃ to represent the northern-limit distribution of warm-temperate forest zone, at least in Korea. Further researches on the reciprocity between floristic regions and phytoclimate zones are raised.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.141-152
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• 1993

A generalized method is presented for shape design sensitivity analysis of axisymmetric thermal conducting solids. The shape sensitivity formula of a general performance functional arising in shape optimal design problem is derived using the material derivative concept and the adjoint variable method. The method for deriving the formula is based on standard axisymmetric boundary integral equation formulation. It is then applied to obtain the sensitivity formulas for temperature and heat flux constraints imposed over a small segment of the boundary. To show the accuracy of the sensitivity analysis, numerical implementations are done for three examples. Sensitivities calculated by the presented method are compared with analytic sensitivities for two examples with analytic solutions, and compared with sensitivies by finite difference for a cooling fin example.

• The Journal of the Korea Contents Association
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• v.9 no.3
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• pp.336-344
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• 2009

This study is to examine the relationship between leisure activities, job satisfaction and quality of life among security agents. To attain the goal of the study described above paragraphs, private guards held in Seoul and Gyeong-Gi were set as a collected group. Then, using judgment sampling method, finally drewout and analyzed 333 peoples in total. The result of reliability analysis check up was here below; Chronbach's $\alpha$= .665-.816. The conclusion drawn from this study is as follows: First, it make no difference between leisure types in job satisfaction. Second, there is a difference between leisure type in quality of life. Third, the level of leisure activities results in the indirect, direct effect on quality of life through job satisfaction. Job satisfaction is an important variable intermediating the relationship between leisure activiteis and quality of life.

• Survey Research
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• v.10 no.1
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• pp.33-56
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• 2009

Landline telephone surveys of the population of households or individuals in Korea often use telephone directories as sampling frames. Recently, the frequency of unlisted numbers in the directories has been increased and the number of households without landline phones has become larger with a spread of mobile phones. Landline telephone coverage has currently reached to a level that raises concerns about the currently due to a coverage bias on the statistics in question. In this paper, we first present the distribution of telephone ownership in Korea and make a comparison with some selected countries. Second, we describe the characteristics of telephone directories. Next, we directly or indirectly estimate the telephone coverage rates of the frames, and show that it may nationally be lower than 65.6% based on additional information. We conclude with remarks about future studies to reduce coverage bias, including the developments of efficient random digit dialing sampling methods.

• Journal of the Korean Society for Library and Information Science
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• v.43 no.4
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• pp.117-137
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• 2009

This study aims to grasp how to understand the difference in return on investment (ROI) or the cost-benefit ratio in forty-two domestic and overseas studies of library valuation, using a meta-analytical review method. Meta-analysis, a quantitative analysis on the findings of previous studies, was conducted to gather the general findings and lessons from prior empirical research. The results of meta-regression analysis indicate that the pattern of findings is consistent with our expectations regarding the effect of benefit scope and per capita GDP included in the ROI figure. This study appears to be the first meta-analytical review conducted on library valuations and the findings provide strong implications for the policy-making process.

• Journal of The Korean Association For Science Education
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• v.21 no.1
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• pp.59-75
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• 2001

While previous studies have recognized and have researched the resistance of students' scientific conception to change and the difficulty of the change of a conception's status, few have investigated the idea of conceptual ecology as a context of conceptual change learning, including the role that affective and motivational aspects might play when students are exposed to conceptual change learning, The present study was conducted to describe in detail high school students' views about learning and knowing science by summarizing of students' conceptual ecologies. The study was interpretive, using multiple data sources to achieve a triangulation of data. Three students from a public high school for boys serve as cases representative of students' views about learning and knowing science. Students' enthusiasm to pursue science was closely connected to their views about learning and knowing science. Students' views about learning and knowing science are influenced by their views regarding science and science class including the nature of knowledge, learning, and their epistemological commitments, They influence students' self-efficacy and motivation on learning science.