• The Journal of the Korea Contents Association
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• v.17 no.8
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• pp.382-395
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• 2017

This study tries to analyze whether the Earned Income Tax Credit (EITC), which was modified in 2011, has the effect of work incentive. In this sense, by establishing the 8th Wave of Korea Welfare Panel Study (2013) and the 9th Wave (2014), Furthermore, in order to overcome the methodological limit, the results of two-party analysis method will be compared by firstly carrying out multiple regression analysis and then performing propensity score matching analysis. The 535 households out of 6,025 were selected. The following are the results of multiple digression analysis and propensity score matching analysis. First, there was no statistically meaningful relationship with regard to the perception of the EITC. Second, there was a statistically meaningful result in the reduction of working hours with regard to whether a household received labor incentive or not. The study found that the revised EITC is not providing incentives which stimulates the will to work.

• Korean Journal of Environment and Ecology
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• v.11 no.2
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• pp.149-159
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• 1997

Eleven plots(10m*10m) were established in Pinus densiflora forests and analized in with TWINSPAN and DCA techniques, to study the comparison of the structure of plant community by soil depth in Ulsan Grand Park. As a result of this analyusis, the communities were divided into two groups : Community B which have shallow one. Community A showed climatic climax which have proceeded from Pinus densiflora to Quercus variabilis, Castanea crenata, Platycarya strobilacea, and at last to Carpinus laxiflora. Community A showed climatic climax which have proceeded fro, Pimus densiflora to Quercus variabilis, Castanea crenata, Platycarya strobilacea, and at last to carpenus laxiflora. Community B showed edaphic climax in sere of Pinus desiflora. The diffrernce of the growth of tree height was showed significantly between two communities. The sample tree aged 30 in Community A was 8.50m high and the sample tree aged 35 in Community B was 3.80m high. Community A was better than Community B in soil characteristics and species diversity indicies.

• Korean journal of applied entomology
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• v.9 no.2
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• pp.81-84
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• 1970

The occurence of apple canker in the three main apple growing areas including Yesan, Chungju and Taegu was investigated during the four years from 1967 to 1970. According to the survey, about 30 percent of apple plants was infected with canker organisms and more the disease occurred in older plants in comparison with younger ones. Jonathan was said to be highly susceptible among five varieties observed. Main trunks or main branches had more canker lesions than those of twigs or of side branches. The survey showed that application of higher nitrogenous fertilizer without boric acid predisposed to the disease together with sandy soil.

• Korean Journal of Organic Agriculture
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• v.22 no.1
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• pp.115-127
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• 2014

This study was conducted to select environmental friendly organic materials for controlling the main disease of Yuzu (Citrus junos Sieb). Meloanose caused by Phomopsi scitri and Scab caused by Elsinoe fawettii are the most common disease in Yuzu. In this study, of which Meloanose disease severity was severe at late of June corresponded with high humidity due to frequent rainfall at that time. In addition, occurrence of two disease have shown in old tree than young. After processing with environmental friendly organic materials, reduction of disease severity was 51~73% and 41~75% in case of Meloanose and scab, respectively. Based on result, environmental friendly organic materials tested in this study may source for controlling both Meloanose and scab diseases on Yuzu.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.174-180
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• 1995

The damage rate according to the age of black pine trees in the Black pine bast scale, Matsucoccus thunbergianae was high from 7 to 22 year old trees. According to damaged degree of damaged trees, it showed great difference in infection rate of saprophitic fungi. The period until the developmental degree of saprophitic fungi became maximized degree of 7 was required about 48 days in dead tree of 100 percent, about 54 days in one of above than 80 percent, about 75 days in one of 40~50 percent, but the dead tree less than 10 percent and health tree was retained the 3~4 developmental degree of saprophitic fungi, after 80 days. The ring width of damaged trees showed as follows. The non damaged trees was 3.52 cm, 0.77 cm in the damaged trees of 100 percent, 0.88 cm in the ones of 80 percent, 1.22 cm in the ones of 40~50 percent and 1.37 cm in the ones of les than 10 percent, respectively. Number of cells per unit area was smaller in the case of greater damaged trees, gradually. Also moisture content was very high in greater damaged trees, and bending strength was lower. Extracts by the one percent NaOH showed a small amount.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.53-59
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• 2001

This study was carried out to investigate mass propagation technique by using seed and vegetative propagation of Kalopanax pictus Nakai. For developing seed propagation, seed stratification and 1$0^{\circ}C$ after-ripening treatment induced embryo growth within 1 weeks, resulted in increasing germination rate of seeds up to more than 65% when planted. The softwood cutting using one year old shoot increased rooting rate to 69% whereas more than 1 year old shoot looked like inappropriate for cutting propagation. In the cutting timing, the rooting rate on June, 13 cutting of the first growth shoot was the highest, followed by June 20 and July 4. The most efficient cutting timing seemed to be the middle of June. When cutted shoots were soaked for 30 minute with IBA and NAA 1000mg.$L^{-1}$, rooting rate was increased above 70%. As the concentrations of plant hormone were increased above 2000mg.$L^{-1}$, the rooting rate was slowly decreased.

• Journal of the Economic Geographical Society of Korea
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• v.13 no.4
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• pp.663-680
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• 2010

This paper aims at analysing Regional Patterns of Farmland Price Changes for the Farmland Reverse Mortgage System. Farmland Reverse Mortgage(FRM) is a system in which the aged farmers in the rural areas receive certain amount of money monthly through the liquidation of their own farmlands for the life time. Farmland price affects the farmland annuity considerably. In the future, if the farmland price goes down than the price when the borrower joined FRM, the borrower can get profits from the pension. Based on the results, the farmland price of Kyeonggi-do is strongly related to economic growth rates(index of industrial product). while that of Gyeongsangbuk-do is weakly related to economic variables including economic growth rates. Therefore, the expectation of farmland value rising rate will be higher in Kyeonggi-do than in Gyeongsangbuk-do. Thus the number of borrowers who want to join FRM in Gyeongsangbuk-do will be more than those in Kyeonggi-do.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.397-401
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• 2005

Homoharringtonine isolated from the plumyew tree (Cephalotaxus koreana) is currently considered as one of the most promising chemotherapeutic agents for anti-cancer. Variation of homoharringonine contents from eight natural populations of Korean native plumyew trees was determined by HPLC (high performance liquid chromatography), and compared with the variation among populations, the variation of the different parts(needle, root, stem and seed), and the variation according to their ages and growth features. Homoharringonine contents among populations were significantly different with Mt. South Dukyu ($1,048{\mu}g/g$) having the highest and Mt. Obong having the lowest. The analyses of plant pans showed that the homoharringtonine contents were highest in plant needles ($874{\mu}g/g$), and followed by roots, stems and seeds. Homoharringtonine contents of the plumyew trees decreased about 30% in increment with their ages and growth.

• Research in Plant Disease
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• v.11 no.1
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• pp.10-15
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• 2005

The occurrence of melanose was investigated on yuzu at Goheung and Boseong in Jeonnam province in 1997 and 1998 seasons. The disease occurrence on leaf was initiated from late May in 1997 and early May in 1998, severest in late of June on leaf, and in case of fruit, initiated from early July in 1997 and late June in 1998 with a peak in early August. The disease was occurred in twenty days more earlier in 1998 season than 1997 season. We think this was caused by temperatures during April and May. And it was supposed that the disease severity on the severest late of June was closely related to the rainfall and relative humidity during June. The disease severity was severer in old tree than the young.

• Journal of Korean Society of Forest Science
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• v.22 no.1
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• pp.67-70
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• 1974

Experiments were carried out to find the difference of resin canal numbers by tree age and topophysis of crown of black pine needles, and the results were summarized as follows. 1. The average numbers of resin canal by tree age were increased from the age of 5 years were not difference between 10 and thereafter years significantly. 2. In this observation, the range of resin canal number was 2 to 9. 3. The numbers by the topophysis of crown did not show significant differences but the individual trees showed significant variations in the canal number in younger trees.