• Title/Summary/Keyword: panel test

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The Return to Education and Sheepskin Effect in Korea: Comparison of Male and Female Workers (한국의 교육투자수익률 및 학위효과 : 남녀 비교)

  • Han, Sung Shin;Cho, In Sook
    • Journal of Labour Economics
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    • v.30 no.1
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    • pp.1-30
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    • 2007
  • Using the Korean Labor and Income Panel Study 2001 (KLIPS 2001), this paper examines gender differences in the return to education in Korea. On average, there is little difference in return to education between male and female workers. However, this paper provides evidence that the impact of education on wages is greater for female workers compared to that for male workers using three different estimation strategies. First, a simple cohort analysis shows that the estimated returns to education for male and female workers have different patterns by age cohort and this is the main reason we observe little gap in average returns to education between men and women. Second, we find that college degree has a significant impact on women's labor market outcomes, while there is little gain for men in terms of wage levels by having college degree. Finally, when controlling unobservable individual ability level with test scores, education has no significant impact on male workers' wage levels, while the impact of education on wages is considerably large for female workers. All three findings support that the impact of education on labor market outcomes is greater for female workers compared to that for male workers as many researchers have found in other OECD countries.

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Trajectories of Mothers' Daily Life Stress and its Association with Early Adolescents' Perceived Neglecting Attitude and Academic Achievements in Multicultural Families: Growth Mixture Modeling (다문화 가정 어머니의 일상생활스트레스 변화 양상에 따른 방임 및 자녀의 학업성취 차이: 성장혼합모형 적용을 중심으로)

  • Yun, Hongju;Choi, Hyo-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.12
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    • pp.348-356
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    • 2019
  • The purpose of this study was to identify latent classes in changes of mothers' daily life stress over six years from multicultural families and to test its relationship with early adolescents' perceived neglecting parental attitudes and their academic achievements. For achieving this purpose, as the study sample 1,039 students were gathered from the 4th grade of elementary school to 3rd grade of middle school, using Growth Mixture Modeling, Multiple Group Analysis, and One-way ANOVA. The results were as follows. First, latent classes of mothers' daily life stress were categorized into three types: high-stable trajectory, moderate-changing trajectory, and low-changing trajectory. Second, these three types showed different characteristics in early adolescents' perceived neglecting parental attitudes and academic achievements. Third, early adolescents' perceived neglecting parental attitude were not significant determinants of the latent classes while academic achievements were. The findings of this study may provide a framework for understanding the relationships among mothers' daily life stress and early adolescents' perceived neglecting parental attitudes and their academic achievements in multicultural families and practical implications for providing social support to overcome daily life stress of mothers in multicultural families.

Related Party Transactions and Corporate Value: Test of the Efficient Transaction and Conflict of Interests Hypothesis (특수관계자간 거래와 기업가치: 효율적 거래가설과 이해상충가설 검증)

  • Lee, Sang-Gyu;Kim, Byoung-Gon;Kim, Dong-Wook
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.9
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    • pp.446-453
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    • 2018
  • This study analyzed the effect of related party transactions on the corporate value of Korean firms using panel data regression analysis. We tested the efficient transaction hypothesis and conflict of interests hypothesis which concern related party transactions. Five types of related party transactions were considered, including long term supply contracts, assets and business transfers, affiliate loans, equity investment, and credit offerings. If related party transactions were conducted for the purpose of enhancing corporate efficiency, results would have a positive effect on firm value. If related party transactions were conducted for the purpose of private profits of the controlling shareholders, the results would show a negative effect on firm value. Results were as follows. Firstly, it is confirmed that affiliate loans, equity investment, and credit offerings had negative effects on firm value. This implies that these types of related party transactions used by controlling shareholders for the purpose of their private profit, which supports the conflict of interests hypothesis. Secondly, it was found that long term supply contracts and assets and business transfers had no effect on firm value.

Effect of various additives on reduction of unpleasant odor and inhibition of Bacillus cereus growth in cheonggukjang (다양한 첨가제에 의한 청국장 불쾌취 및 Bacillus cereus 증식의 억제)

  • Jeong, Su-Hyeon;Park, Song-Yie;Jeong, Eun-Seon;Kim, Yong-Suk;Mun, Sung Phil
    • Korean Journal of Food Science and Technology
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    • v.48 no.6
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    • pp.569-573
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    • 2016
  • The effectiveness of various additives in reduction of an unpleasant odor and inhibition of Bacillus cereus growth in Cheonggukjang (CKJ) was investigated. Sensory evaluations of unpleasant odor intensity and taste preference for CKJ were conducted with a 5-point scale. Raw CKJ was rated to have the highest unpleasant odor intensity, followed by CKJ-salt, CKJ-wood vinegar salt, CKJ-red pepper seed oil, and CKJ-bamboo salt in the given order. The test panel had a greater preference for CKJ-red pepper seed oil than for the other CKJ products. The addition of bamboo salt to CKJ was the most effective in inhibition of B. cereus growth in comparison to the other three additives. Volatile compounds in CKJ and CKJ-bamboo salt were identified by GC/MS analysis. 1-Ethoxy-1-methoxy-ethane was responsible for the pleasant odor and its level significantly increased in CKJ-bamboo salt. Consequently, adding bamboo salt to CKJ not only masked and reduced the unpleasant odor, but also inhibited B. cereus growth in CKJ.

Utilization of the Protein Hydrolysates of Skipjack Tuna Viscera (가다랭이 내장 단백질 가수분해물의 이용)

  • Kim, Sung-Min;Ha, Jung-Uk
    • Korean Journal of Food Science and Technology
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    • v.27 no.2
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    • pp.141-146
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    • 1995
  • For the effective utilization of skipjack tuna viscera, a study was carried out to investigate the applicability of viscera protein hydrolysate (VPH) as a protein supplement in the processing of imitation sauce and bread. The optimum extraction and hydrolyzation conditions for the production of viscera protein concentrate (VPC) and viscera protein hydrolysate (VPH) were determined. Boiled viscera could be extracted by ethyl alcohol without significant deterioration as a raw material for the further processing. High quality of VPH could be obtained by hydrolysis with 1% pepsin under its optimum condition $(pH\;1.65,\;37^{\circ}C)$. The solubilities of VPC and VPH were 40% and 90%, respectively, and the essential amino acid contents in two products were 48.7% and 63.2%, respectively. Especially, the content of taurine, a physiologically important amino acid, was 9.4% in VPH. In experimental preparations of imitation sauce and bread, panel test showed that the supplementation of 10% of VPH in imitation sauce and $3{\sim}5%$ of VPH in bread was well accepted in sensory characteristics such as color, flavor, taste and texture.

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Effect of Clay Mineral Pegmatite and Vitamin A and Supplements on the Physico-Chemical Characteristics of Fattening Hanwoo Steers (거정석과 비타민 A 급여가 거세한우 등심육의 이화학적 특성에 미치는 영향)

  • Kim Byung-Ki;Go Si-Jang
    • Food Science of Animal Resources
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    • v.25 no.2
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    • pp.156-161
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    • 2005
  • This study was conducted to detennine the effect of dietary supplements of mineral powder (pegmatite) on the physico-chemical properties of M longissimuss for 24 Hanwoo steers. Each eight Hanwoo steers were randomly allotted to three treatments ; Control $(0\%)$, T1 (supplemented with pegmatite $2.0\%$ and vitamin A $0.2\%)$, T2 (supplemented with pegmatite $2.0\%$). Cooking loss was highest in control, while water holding capacity (WHC) was the highest in T2 (56.38) than the others. However, effect of the diets on meat color was not significantly different (p>0.05) Panel test scores of juiciness, tenderness and flavor of M longissinus were the highest for T1 $(4.6\~5.0)$ between the treatment group (p<0.05). The content of total fatty acid in M longissimus was the highest in T2 $(50.80\%)$ among the treatment group. Palmitic acid and oleic acid were siginificantly higher in T1 and control than those for the others(p<0.05). Unsaturated fatty acid (UFA) was highest in T2 $(58.57\%)$ than the others$(55.09\~55.64\%)$ (p<0.05).

Cycllic Seismic Testing of Full-Scale RBS (Reduced Beam Section) Steel Moment Connections (RBS 철골모멘트접합부의 내진거동평가를 위한 반복재하 실물대(實物大) 시험)

  • Lee, Cheol Ho;Jeon, Sang Woo;Kim, Jin Ho
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.557-566
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    • 2002
  • This paper summarized the results of a full-scale cyclic seismic testing on four reduced beam section (RBS) steel moment connections. Specifically, these tests addressed a bolted web versus a welded web connection and strong versus medium panel zone (PZ) strength as key test variables. Specimens with medium PZ strength were designed to promote balanced energy dissipation from both PZ and RBS regions, in order to reduce the requirement for expensive doubler plates. Both strong and medium PZ specimens with welded web connection were able to provide sufficient connection rotation capacity required of special moment-resisting frames. On the other hand, specimens with bolted web connection performed poorly due to premature brittle fracture of the beam flange at the weld access hole. Unlike the case of web-welded specimens, specimens with cheaper bolted web connection could not transfer the actual plastic moment of the original (or unreduced) beam section to the column. No fracture occurred within the beam groove welds of any connection in this testing program. If fracture within the beam flange groove weld is avoided by using quality welding procedure as in this study, the fracture issue tends to move into the beam flange base metal at the weld access hole. Supporting analytical study was also conducted in order to understand the observed base metal fracture from the engineering mechanics perspective.

Racking Property of Light-framed Shear Wall with Hold-down Connector (홀드다운을 적용한 경골목조 벽체의 전단성능)

  • Lee, In-Chan;Park, Chun-Young;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.36 no.4
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    • pp.26-36
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    • 2008
  • As the height of the light-framed building increases, the lateral load and overturn-moment are increased and the possibility of the building overturn becomes larger. Because the shear wall resists lateral load in light-framed building, the reinforcement of shear wall is required. In order to reinforce the light-framed shear wall, using lag screw fastener type (B-HD) and using bolt type (S-HD) hold-down connectors were applied for test. And domestic larch lumbers, $38{\times}140mm$ and $89{\times}140mm$, KS 2nd grade, were used for the stud. The North American OSB panels were used for sheathing panel. Static loads, load speed 6 mm/min, were applied on top of the wall. As a result, shear strength of the wall that using hold-down connector was improved sufficiently. And when applying the S-HD type hold-down connector, stud should be reinforced against weakening by drilled hole. As increasing the number of lag screw, the number of bolt and the product allowable strength, the strength of shear wall that using hold-down connector was also increased. When applying hold-down connector to light-framed building using 38 mm stud, it must be reinforced by enlarging the thickness of stud like as 38 mm doubled column.

Changes in Palatability of Cooked Rice by Blending High Quality Rice or Glutinous Rice to Low Quality Rice and by Blending Rice of Different Varieties (불량식미쌀에 대한 우량식미쌀 및 찹쌀의 혼합과 쌀의 품종간 혼합이 밥맛에 미치는 영향)

  • Yong-Woong Kwon;Je-Cheon Chae;Jeon-Woo Bang
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.36 no.4
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    • pp.351-359
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    • 1991
  • Demand for the rice of better eating quality is ever increasing in recent years. However. the rice is presently handled by the government and merchants as mixture of the rice of different varieties from the purchase of the rough rice to storing and milling. It is well known that the eating quality of rice varies significantly by variety. The present study aimed at evaluation of the effect of blending different rices on the change in palatability of low and high eating quality rices. The eating quality of a low quality japonica rice was improved significantly on sensory panel test by blending it with the Dongjin rice. one of the highest eating quality. only when the Dongjin was blended to 80 percent by weight. and also it was same for blending an ordinary quality rice of mixed varieties which has been stored by a governmental storehouse with a top class rice on free market. The eating quality of aged Tongil type rice. produce of 1987 and 1989 and a mixture of varieties, was improved significantly by blending it with a high quality glutinous rice on market to 20 per cent by weight. But Samgang rice. a high eating quality Tongil type variety. and an ordinary quality rice of Japonica varieties were not significantly improved by blending them with the glutinous rice by 20 per cent. Blending rices of the variety Nagdong. ordinary quality among varieties and low quality among Japonicas, Chucheong, a high quality rice among Japonicas. and Dongjin. one of the best eating quality rice among Japonicas, each other in different ratios did not affect significantly the sensory scores.

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Analysis of Acetaldehyde and Formaldehyde Migrated from Polyethylene Terephthalate Bottles into Mineral Water (페트병 생수 중 아세트알데하이드와 포름알데하이드의 이행 분석)

  • Jung, Eui-Min;Kim, Dong-Ju;Lee, Keun-Taik
    • Korean Journal of Food Science and Technology
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    • v.43 no.4
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    • pp.504-508
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    • 2011
  • The objective of this study was to determine the extent to which acetaldehyde (AA) and formaldehyde (FA) migrated from polyethylene terephthalate (PET) bottles into mineral water during storage at 25 and 35$^{\circ}C$ for 240 days. Generally, AA and FA were observed to migrate more at 35$^{\circ}C$ than at 25$^{\circ}C$. The amount of FA in the samples irradiated under UV lamps was higher than in those stored in the dark over the storage period and vice versa for AA. Using a triangular test, the sensory panels distinguished a difference between one sample and the other two mineral water samples that had been exposed to UV lamps after 60 days of storage at 35$^{\circ}C$ (p<0.05). At this time, FA and AA concentrations were measured at 267.4 and 515.3 g/L, respectively. After 120 days, an independent mineral water sample from the other two samples in all treatments could be distinguished by the panel members at a significance level of p<0.001.