• Journal of Digital Convergence
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• v.17 no.5
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• pp.295-301
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• 2019

This study examined the effect of insecure attachments, depression, life satisfaction on SNS addiction tendency. Participants were recruited from 3 universities in Seoul, Daejeon and Kyungbook Province. Participants were given the survey including instruments that measured adult attachment, depression, life satisfaction, and SNS addiction tendency. Total 310 participants' data were used for analysis. Multiple regression revealed that SNS addiction tendency was predicted by anxious attachment(${\beta}=.32$, p<.001), depression(${\beta}=.17$, p=.003), and gender(${\beta}=-.25$, p<.001), except life satisfaction, and 26% of the variance was explained by these variables. These findings can help to expand the understanding and the development of the effective prevention/intervention programs of SNS addiction tendency for university students.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.407-415
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• 2024

This study used data from the 9th main survey of the National Old Age Security Panel, the subjects were 1,923 elderly people aged 60 or older nationwide. As a result of analyzing the effect of demographic characteristics on Preparing for Oldage, 15.1% of explanatory power was shown in Preparing for Oldage. First, it was found that there was more Preparing for Oldage among men than among women. Age had a negative effect on Preparing for Oldage, with many respondents saying that the younger they were, the more likely they were to Preparing for Oldage. Education level also had a significant effect on Preparing for Oldage, and more respondents said that elementary, middle, and high school graduates were not doing Preparing for Oldage than those who graduated from vocational college or higher. Therefore, it was found that the lower the level of education, the less Preparing for Oldage was done. Next, as a result of examining the effect of life satisfaction on Preparing for Oldage, the higher the life satisfaction, the better the Preparing for Oldage was. In general, it was recognized that Preparing for Oldage would have an impact on life satisfaction, but through this study, it was confirmed that life satisfaction had an impact on Preparing for Oldage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.670-676
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• 2017

The purpose of this study is to analyze the shipbuilding structure of Hallabong Tangorover ten-day and monthly intervals, to determine whether the shipment control can stabilize and increase the income of Hallabong Tangor farmers by estimating and analyzing the price flexibility function of Hallabong, and to derive the policy implication. Looking at the overall market, the 1% increase in shipment volume indicates that the coefficient of price flexibility varies with time. The largest decline is in late December and early January. The dummy variable indicating the year in which the quality drops somewhat is statistically significant from March to May, and the average of them is -0.337%. This implies a greater importance for quality control and shipment control when quality is worse than good quality. The price flexibility, which indicates price changes due to 1% increase in monthly shipment volume of Hallabong Tangor, varies with time. The coefficient of price flexibility was the highest at -0.46 in December, but prices fell slightly due to quality improvement and the increase in special demand of New Year's demand, which was -0.33% in January, -0.261% in February, -0.307% in March, and -0.318% in April. Since then, the amount of storage has been gradually exhausted, and the price flexibility has fallen slightly to -0.243% in May and -0.236% in June. DUM02, which represents the year when more than 7 days after the New Year holidays are in February is from February to June (+). This indicates that the price decrease due to increase in volume is less than that in January when the New Year is in February. This indicates a greater necessity for shipment control when New Year holidays are in January.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.40-50
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• 2023

Recently, the number of components of smartphones increases rapidly, while the PCB size continuously decreases. Therefore, 3D technology with a stacked PCB has been developed to improve component density in smartphone. For the s tacked PCB, it i s very important to obtain solder bonding quality between PCBs. We investigated the effects of the properties, thickness, and number of layers of interposer PCB and sub PCB on warpage of PCB through experimental and numerical analysis to improve the reliability of the stacked PCB. The warpage of the interposer PCB decreased as the thermal expansion coefficient (CTE) of the prepreg decreased, and decreased as the glass transition temperature (Tg) increased. However, if temperature is 240℃ or higher, the reduction of warpage is not large. As FR-5 was applied, the warpage decreased more compared to FR-4, and the higher the number and thickness of the prepreg, the lower the warpage. For sub PCB, the CTE was more important for warpage than Tg of the prepreg, and increase in prepreg thickness was more effective in reducing the warpage. The shear tests indicated that the dummy pad design increased bonding strength. The tumble tests indicated that crack occurrence rate was greatly reduced with the dummy pad.

• Explosives and Blasting
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• v.20 no.1
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• pp.5-14
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• 2002

파쇄 암석의 파쇄도는 발파효율을 나타내는 중요 척도로서 적재와 분쇄 작업에 큰 영향을 미친다. 그러나 현장에 쌓여 있는 발파암 더미로부터 파쇄도를 조사한다는 것은 용이한 작업이 아니다. 본 연구에서는 석산 발파에서 가장 중요한 요소인 천공방식과 암질의 변화가 파쇄도와 발파진동에 미치는 영향을 조사하였다. 파쇄 입도에 영향을 미치는 중요한 변수인 천공방식, 암질등급(RMR), 현지 암반의 블록 크기, 발파진동 등의 영향을 파쇄암의 평균입도(MFS)와 상위 5개의 대괴 평균치$(L_5)$로 나타내었다. 연구결과, 파쇄암의 평균입도는 상위 5개의 대괴 평균치와 선형적인 관계를 보였다. 발파방법과 파쇄도 평가 결과 재래식 발파에서는 파쇄도를 예측할 수 없었고 커다란 옥석이 생성되었으나, 벤치발파에서는 평균파쇄암의 크기가 비교적 양호한 파쇄 상태를 유지하였다. 현지 암반 블록 크기는 평균 파쇄암의 크기와 선형적 관계를 나타내었다. RMR값이 커짐에 따라 발파진동 추정식의 진동상수 K와 감쇠지수 n의 절대값과 평균 파쇄암의 크기, 그리고 상위 대괴의 크기는 대체적으로 증가하는 경향을 나타내었고, 진동상수 K와 감쇠지수 n도 증가하는 경향을 보였다.

• Journal of the Korea Convergence Society
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• v.10 no.3
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• pp.193-201
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• 2019

The public's interest regarding multi-household houses, one of the small-scale housings used as profit earning property, has been increasing. Previous studies regarding price, such as the rent and sales price of multi-household houses', however, were difficult to find. Thus, this study set forth to find out what characteristics influence the sales price of multi-household houses so as to provide further suggestions to investors' decision makings and developers' strategy establishments. The data was retrieved from multi-household sales transacted in Changwon City. Through empirical analysis, this paper found that prices were high in Euichang-gu and Seongsan-gu, and meaningful variables in terms of locations were distance from major trade areas(-), distance from main streets(-), and Corner site(+). Meaningful variables related to household characteristics were total floor area(+), Studio type(+), Southern exposure(+), Building age(-), and Full-furnished(+).

• Journal of Technology Innovation
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• v.23 no.3
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• pp.373-396
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• 2015

This study analyzed the determinants of high-growth firms using the technology appraisal data of the Korea Technology Finance Corporation. This study is differentiated from previous studies for three reasons. First, it analyzed the determinants of firms that will grow into high-growth firms in the future, not the characteristics of current high-growth firms. Second, it analyzed high-growth firms by dividing them in two aspects: sales and employment. In other words, they were divided into three types: the case in which a firm achieves high growth in both sales increase and creation of jobs, the case in which a firm achieves high growth in creation of jobs but low growth in sales increase, and the case in which a firm achieves high growth in only sales increase but low growth in creation of jobs. Third, this study applied the technology appraisal indicators of Kibo Technology Rating System(KTRS) by the Korea Technology Finance Corporation as the explanatory variable. As a result of analysis, it was found that a firm achieved high growth in both sales and employment if the position in the technology life cycle was appropriate and the technology readiness level was high. However, it turned out that the management system of technical manpower had conflicting effects on high growth of employment and sales. In other words, a firm that had well managed its technical manpower achieved high growth in terms of employment, but rather showed low growth in terms of sales. This result suggests the inference that firms showing high growth in employment may appear mainly in the high-tech industry where management of technical manpower is important. Accordingly, as a result of adding dummy variables that represent whether or not firms are in the high-tech industry, it was found that the result supported the inference, as firms in the high-tech industry were highly likely to achieve high growth in employment.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.80-92
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• 2017

This paper attempts to estimate the diesel fuel demand function in Korea using panel data panel data of 16 major cities or provinces which consist of diesel demands, diesel market prices and gross value added from the year 1998 to 2015. I apply panel GLS(generalized least square) model, fixed effect model, random effect model and dynamic panel model to estimating the parameters of the diesel fuel demand function. The results show that short-run price elasticities of the diesel fuel demand are estimated to be -0.2146(panel GLS), -0.2886(fixed effect), -0.2854(random effect), -0.1905(dynamic panel) respectively. And short-run income elasticities of the diesel fuel demand are estimated to be 0.7379(panel GLS), 0.4119(fixed effect), 0.7260(random effect), 0.4166(dynamic panel) respectively. The short-run price and income elasticities explain that demand for diesel fuel is price- and income-inelastic. The long-run price and income elasticities are estimated to be -0.4784, 1.0461 by dynamic panel model, which means that demand for diesel fuel is price-inelastic but income-elastic in the long run. In addition I apply dummy variable model to estimate the effect of 16 major cities or provinces on diesel demands. The results show that diesel demands is affected 10 regions on the basis of Seoul.

• Environmental and Resource Economics Review
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• v.19 no.1
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• pp.101-127
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• 2010

The purpose of the research is to tackle proximity effects (PEs) when nonmarket valuation method CVM is applied to environmental goods such as tidal flats. 1,000 households are surveyed in the ratio of national household for the research. The sample are reclassified into five areas by 30-minute distance. Log-linear are used to analysis PEs in the research. On conclusion log-linear model regarding income effects proves that PEs are apparently represented in NMVMs(${\theta}_1$ >0. ${\theta}_2$ >0 and $dum1{\neq}0$, $dum2{\neq}0$, $dum3{\neq}0$, $dum4{\neq}0$) as a result of a 5 per cent significant level of t -test and F-test, finally rejecting the null hypothesis. In addition, WTP of area I respondents shows 26 per cent more then that of area V respondents, which is from \87,969 to \64,866 in the open-ended format. Finally, the research proves that the PEs in CVM are evidently represented with the econometric model, hence the PEs have to be embedded into the questionnaire of non-market valuation methods with the environmental goods to reduce the underestimation and improve the estimation accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4784-4790
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• 2013

As with fast growing globalization, Korean firms have increased their offshoring activities and more empirical research are needed to analyze the effect of offshoring on Korean firms' productivity. This study used "Survey of Business Activities", a firm-level panel data set surveyed by the Statistics Korea between 2006 and 2008, and estimated pooled OLS and Panel fixed effect model to examine the impact of offshoring on a firm's labor productivity. Unlike the previous studies on offshoring, we included in the analyses the firms in the service industry in addition to those in the manufacturing industry, and presented the comparative results. The results from pooled OLS model show that 1% increase in the share of offshoring output will lead to 0.03% increase in labor productivity. However, the results from Panel model show that the effects of offshoring on productivity is positive but statistically insignificant. Analyzing the manufacturing and the service sector separately, the main results based on Panel model can be summarized as follows: Offshoring has significant positive effects on firms' productivity in the manufacturing industry. Contrastingly, the impact of offshoring on firms' productivity in the service industry is estimated to be negative but statistically insignificant. Other than the share of offshoring output, most factors except headquarter location have positive effects on firms' productivity in both manufacturing and service industry.