• Fibers and Polymers
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• v.7 no.1
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• pp.70-72
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• 2006

This paper discusses the inter fiber cohesion in man made and blended yarns. The fiber parameters such as fiber length and fineness influence the cohesion. Studies have been focused on polyester and viscose spun yarns. Though polyester and viscose yarns show similar trend in cohesion, viscose yarns exhibit better cohesion clue to their serrated cross section. Studies on the effect of blend proportion of polyester cotton and polyester viscose yarns reveal that increase of polyester and viscose in the respective blends improve the inter fiber cohesion.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2122-2126
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• 2007

A special PM-Tube(Photo Multiplier Tube) that is using the photoelectric effect has been designed and manufactured to measure the radiation energy of arc in a gas circuit breaker(GCB). The PM-Tube, LLG(liquid light guides), ND(neutral density) filter, and a model gas circuit breaker have been combined for the reception and the transmission of the light and a simplified synthetic test facility with the arc energy measuring system has been established. In the case of $SF_6$ gas pressure $5kg.f/cm^2$ and arc length 20mm, the radiation energy increases with the arc current but it tend to be saturated in the above 20kA. Under the arc current 20kA, the total radiation energy has the biggest value around 8kA and was not exceeded 40% of the total arc energy.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.37-46
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• 2009

As the level of technology and the standard of living improve, product reliability plays an increasingly significant role. This study has been performed to build a reliability model of electronic ballasts for the low wattage fluorescent lamp. Telcordia SR-332, one of the most widely used reliability specifications, was selected for the model development. We briefly reviewed the basic concepts of the electronic ballast. We then developed a reliability model for the ballast using SR-332 concepts and the reliability has been examined. We further discussed the significance of the first-year failure effect on the mean life.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.1 s.173
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• pp.190-195
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• 2000

It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a structure. Nikolakopoulos et. al. used the intersection point of the superposed contours that correspond to the eigenfrequency caused by the crack presence. However the intersecting point of the superposed contours is not only difficult to find but also incorrect to calculate. A method is presented in this paper which uses optimization technique for the location and depth of the crack. The basic idea is to find parameters which use the structural eigenfrequencies on crack depth and location and optimization algorithm. With finite element model of the structure to calculate eigenfrequencies, it is possible to formulate the inverse problem in optimization format. Method of optimization is augmented lagrange multiplier method and search direction method is BFGS variable metric method and one dimensional search method is polynomial interpolation.

• Journal of the Korean Geographical Society
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• v.48 no.2
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• pp.239-258
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• 2013

This study aims to examine that Jeollabuk-do 14 cities and counties's job creation policy would lead to a virtuous circle of the local economy through measuring the ratio of spatial mismatch. We suppose that the higher proportion of spatial mismatch in a city or county is, the lower multiplier effect contributes the local economy, especially in the income of residents and the influx of population. For the analysis, this study uses Korean Regional Employment Survey Micro-data and calculates the labor demand self-sufficiency(LDSS) rate of every local labor market for measuring the degree of spatial mismatch. Also we calculate the LDSS rate of employment status, industry, job classification and wage for testing the independency of local labor market. After analyzing, just Jeonju, Gunsan, Iksan, and Namwon could be regarded as independent local labor market where LDSS rates are above 75% in most criteria. But other local labor markets depend on outer labor supplies. For the development of regional economy, it is necessary to consider the creation of 'good jobs' that can induce the labor in parallel with the quantitative increase of employment.

• The Journal of the Acoustical Society of Korea
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• v.40 no.5
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• pp.408-416
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• 2021

In the ultrasonic dispersion, in order to avoid direct contact of the radiation surface of ultrasonic transducers with a liquid sample, the liquid sample is separated by a glass container and it receives ultrasonic energy through an acoustic medium. The transmission efficiency of the ultrasonic energy in the multi-layered ultrasonic system is an important factor. In this study, we suggested a method that can improve the ultrasonic energy transfer efficiency by using a propylene glycol solution as a liquid matching layer in the multi-layered acoustic system. In this method, a propylene glycol solution was filled between the Langevin-type ultrasonic transducer and the luminol solution and the sonoluminescence phenomena in the luminol solution, which is caused by nonlinear effect of high power ultrasound radiated from the transducer, was examined by using a Photo Multiplier Tube (PMT). The transmission efficiency depending on the concentration of propylene glycol solution was observed, and we can see that as the concentration of the propylene glycol solution increased, the matching effect increased while the acoustic attenuation increased. It was confirmed that there is an optimal concentration compromised these two conflicting conditions, and the optimum concentration of the propylene glycol solution was determined experimentally.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.323-332
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• 2019

The purpose of this study is to measure the effects on the regional economy from the Jeju International Wind Ensemble Festival. In order to examine the economic ripple effects of the festival, we examine its impact on the local economy using two regional (Jeju-National) industry-related models based on the 2013 Jeju Region Input and Output Table. We also compare how the Jeju International Wind Ensemble Festival is growing and affecting the regional economy through a comparison between 2017 and 2018. Comparing the results of a production-inducing and value added-effect analysis of the induced industries from investment expenditures for the Jeju International Wind Ensemble Festival, the production-inducing effects increased by 2.1 times-from 9.05 billion won in 2017 to 18.7 billion won in 2018. The value-added effect increased by 2.2 times, from nearly 4.3 billion won in 2017 to nearly 9.2 billion won in 2018. The analysis shows that the Jeju International Wind Ensemble Festival contributes greatly to an income increase for local residents. In order to enhance the effects of the Jeju International Wind Ensemble Festival, it is necessary to use policies that link culture and tourism in Jeju.

• Journal of Wetlands Research
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• v.15 no.2
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• pp.159-164
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• 2013

The 4 major rivers restoration project (4RRP) requires the government to invest a lot of money. Regional economic effect is one of the main purposes of implementing the 4RRP. This paper attempts to measure the regional economic effects, focusing on regional employment-inducing effect and regional income-inducing effect. Regional employment-inducing effect is computed by excluding indirect effect and directly investigating the amount of employment. To this end, marginal propensity to consume, household consumption, household income should be derived. We used working day data and government expenditure multiplier to measure local employment creation and income generation. As a result, the project creates 46,628 employments from 2009 to 25 August 2011 and generates 25 trillion won regional income for three years.

• Journal of the Economic Geographical Society of Korea
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• v.20 no.1
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• pp.84-104
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• 2017

In this study, we divided Gyeonggi-do into Northern, Southern, Western, and Eastern Parts and found out fiscal variables which affected regional economic growth of each Part differentially. And we drew the strategy for economic growth of each Part. After we found out the variables which affected regional economic growth using fixed-effect model, we carried out causality test to determine whether a specific fiscal variable caused economic growth. In the Eastern Part, local tax revenues had a significant effect on the economic growth. Total expenditures, current expenditure in the Southern Part and social welfare expenditure, expenditure on industries, current expenditure in the Northern Part had noticeable effects on economic growth respectively. And we calculated multipliers of fiscal variables to compare the magnitudes of effects among these Parts.

• Journal of Korea Port Economic Association
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• v.24 no.2
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• pp.265-287
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• 2008

This paper studies the economic effects of port-liquid freight by focusing on Ulsan port and its regional economic effects. The direct industrial effects of port-liquid freight are analysed to be an increase in about 1billion dollars' worth of production of the regional port-logistic industry, an increase in about 0.22billion dollars' worth of value-added of the industry, and the creation of about 2,600 employment in the industry. Including the indirect effects, the total effects on Ulsan regional economy are estimated to be an increase in about 1.9billion dollars worth of production, an increase in about 0.51billion dollars' worth of value-added and an increase in about 6,442 employment.