• The Korean Journal of Air & Space Law and Policy
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• v.28 no.1
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• pp.3-54
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• 2013

Nowadays, major advanced countries in aviation technology are putting their effort to develop commercial and civil Unmanned Aircraft System(UAS) due to its highly promising market demand in the future. The market scale of commercial and civil UAS is expected to increase up to approximately 8.8 billon U.S. dollars by the year 2020. The usage of commercial and civil UAS covers various areas such as remote sensing, relaying communications, pollution monitoring, fire detection, aerial reconnaissance and photography, coastline monitoring, traffic monitoring and control, disaster control, search and rescue, etc. With the introduction of UAS, changes need to be made on current Air Traffic Management Systems which are focused mainly manned aircrafts to support the operation of UAS. Accordingly, the legislation for the UAS operation should be followed. Currently, ICAO's Unmanned Aircraft System Study Group(UASSG) is leading the standardization process of legislation for UAS operation internationally. However, some advanced countries such as United States, United Kingdom, Australia have adopted its own legislation. Among these countries, United States is most forth going with President Obama signing a bill to integrate UAS into U.S. national airspace by 2015. In case of Korea, legislation for the unmanned aircraft system is just in the beginning stage. There are no regulations regarding the operation of unmanned aircraft in Korea's domestic aviation law except some clauses regarding definition and permission of the unmanned aircraft flight. However, the unmanned aircrafts are currently being used in military and under development for commercial use. In addition, the Ministry of Land, Infrastructure and Transport has a ambitious plan to develop commercial and civil UAS as Korea's most competitive area in aircraft production and export. Thus, Korea is in need of the legislation for the UAS operation domestically. In this regards, I personally think that Korea's domestic legislation for UAS operation will be enacted focusing on following 12 areas : (1)use of airspace, (2)licenses of personnel, (3)certification of airworthiness, (4)definition, (5)classification, (6)equipments and documents, (7)communication, (8)rules of air, (9)training, (10)security, (11)insurance, (12)others. Im parallel with enacting domestic legislation, korea should contribute to the development of international standards for UAS operation by actively participating ICAO's UASSG.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.107-121
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• 2010

We conducted a sensitivity test of Joint UK Land Environment Simulator (JULES), in which the influence of biophysical parameters on the simulation of gross primary productivity (GPP) and ecosystem respiration (RE) was investigated for two typical ecosystems in Korea. For this test, we employed the whole-year observation of eddy-covariance fluxes measured in 2006 at two KoFlux sites: (1) a deciduous forest in complex terrain in Gwangneung and (2) a farmland with heterogeneous mosaic patches in Haenam. Our analysis showed that the simulated GPP was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration for both ecosystems. RE was sensitive to wood biomass parameter for the deciduous forest in Gwangneung. For the mixed farmland in Haenam, however, RE was most sensitive to the maximum rate of RuBP carboxylation and leaf nitrogen concentration like the simulated GPP. For both sites, the JULES model overestimated both GPP and RE when the default values of input parameters were adopted. Considering the fact that the leaf nitrogen concentration observed at the deciduous forest site was only about 60% of its default value, the significant portion of the model's overestimation can be attributed to such a discrepancy in the input parameters. Our finding demonstrates that the abovementioned key biophysical parameters of the two ecosystems should be evaluated carefully prior to any simulation and interpretation of ecosystem carbon exchange in Korea.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.35-45
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• 1997

This study has been carried out to estimate carbon fixation, and carbon NPP based on equation form of $Wt=aD^bH^c$ in natural stand of Quercus mongolica and Quercus variabilis in Chungju. The effect of improvement of environment was also evaluated by estimating sink of $CO_2$ gas in forest ecosystem of Korea in a year. The following effects have been obtained in analysing estimate of allometric equation. Equation form of $Wt=aD^bH^c$ was the most adequate, those of $Wt=a(D^2H)^b$, $Wt=aD^b$ estimate of the biomass and the carbon fixation in Quercus natural stand of Chungju. Total above ground of Quercus mongolica was 130.58 t/ha and that of Quercus variabilis was 137.38 t/ha. Annual production of two stands was 9.96 t/ha/yr, 8.64 t/ha/yr, respectively. Carbon fixation of total above ground was 60.52t C/ha in Quercus mongolica stand, and was 62.22t C/ha in Quercus variabilis stand. Annual fixation of carbon was 4.78t C/ha/yr and 4.28t C/ha/yr, seperately. Annual emission of carbon estimated 2.44t C/ha/yr in contrast of forest area in Korea. It was showed that the annual fixation of carbon was higher 1.84t C/ha/yr~2.34t C/ha/yr than annual emission of carbon. But foliage was 2.39t C/ha/yr and 1.89t C/ha/yr, which occupied 40% and 50% of annual carbon fixation of total above ground. Annual carbon fixation may fluctuate about 1.89t C/ha/yr~2.39t C/ha/yr by seasons.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.325-332
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• 2020

This study was conducted on cultivation farms in the Gimcheon area, which is the main production area of walnuts, in order to compare and analyze the yield and fruit quality of walnut trees (Juglans sinensis Dode) derived from seedlings. The official trees were classified into nine classes from 10 to 60 years old, and a total of 135 trees were selected, with 15 trees selected for each grade. The growth and fruit characteristics for each age group were then examined. The average tree height was 10.3 m, and the average crown area was 63.7 ㎡. The average number of fruit settings per tree was 573.1, with the largest number of walnuts per tree at 35 years (974.0 walnuts), and the lowest walnuts per tree at 10 years (124.7 walnuts). In addition, the number of fruit settings per bearing mother branch in 35 year old trees was the highest at 3.1. The average weight for each fruit type was found to be 58.7 ± 4.0 g of walnuts in green peel, 10.5 ± 0.5 g of dried shell walnuts, and 4.9 ± 0.2 g of walnuts, respectively. The average yield by fruit type was 32.5 ± 13.8 kg of walnuts in green peel, 5.9 ± 2.5 kg of dried shell walnut, and 2.8 ± 1.2 kg of walnuts. The yield was positively correlated with the crown area, the number of fruits setting per bearing mother branch, and the number of fruits setting per 1 ㎥. The formula used to estimate the yield per tree by age was calculated as y = 8993.9 ln (tree age-9) 8230.3, R² = 0.8531 (walnut in green peel) and y = 1647.1 ln (tree age-9) 1442.1, R² = 0.8527 (dried shell walnut).

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.680-689
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• 2006

Introduction of the Special Account for Balanced National Development (SABND) which was represented top-down in 2005 have previous national budget distribution system between central and local government change. A local autonomous entities can choose freely the favorite programs within the total programs in SABND so they can use limited budget efficiently, After induction of this system, budget of the Forest Programs in SABND in 2006 compare to last year has increased by 24.5 percent. That is three times higher than the average rate of total SABND budget, 8.1 percent. This study surveyed propriety of the Forest Programs and hereafter their budget prospect with local government officials in forest sector, 68.7 percent of the respondents recognized that the inclusion of the Forest Programs in SABND is proper. The most preferred Forest Programs are making Urban Forests and their Management and making Facilities for Forest Recreation. And the most non-preferred Forest Programs are complementing the Lumberyard Facility of the Forestry Association, making the Exhibition of Wood Products and making the Base for the Seedling Production. When Forest Programs are adjusted in the future, these programs above mentioned should be exempted from the SABND. because the non-preferred programs as well as the small budget programs On the prospect of the future budget, 81.1 percent of the local government officials in forest sector answered that it will be the same with the current or increasing, In the short term, the budget of the Forest Program in SABND is expected to increase.

• KDI Journal of Economic Policy
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• v.14 no.2
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• pp.29-54
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• 1992

Recent studies on the economic effects of trade liberalization and economic integration have emphasized the significant gains associated with product differentiation and scale economies. Securing access to markets in other countries will make it possible to increase product variety and capture scale economies, thus, expanding the gains from trade. Liberalization is also expected to introduce foreign competition into the previously closed market. Concurrently, the liberalization will improve the competitive market environment for firms selling in the domestic market. Firms will be pressed to either exit or reduce cost. The output per firm, then, will increase due to the exit of rival firms, and the average total cost will decline due to the economies of scale. 'Rationalization' of the production process will eventually follow. This paper addresses the economic effects of (counterfactual) bilateral tariff elimination between Korea and Japan. It computationally assesses the gains from liberalization as well as the resource allocations and welfare effects associated with the tariff reduction. The endogenous determination of the key parameters distinguishes this paper from others. The firm's perceived elasticity of demand and elasticity of substitution in the present model are calibrated to be consistent with the base year data. Korea, Japan, and the rest of the world are modeled explicitly. The sectoral coverage of the model includes twenty-three tradable product categories based on three-digit SITC industries and seven nontradable categories based on one-digit SITC industries. Product categories are also classified into perfectly competitive and imperfectly competitive ones. In the imperfectly competitive industries, product differentiation exists at the firm level, while the perfectly competitive industries are characterized by national product differentiation. The simulation results of bilateral tariff reduction are reported. Tariff elimination tends to increase intra-industry trade flows so that the total amount of exports and imports of both countries expand. Yet, Japan is expected to increase the bilateral trade surplus in the wake of the mutual tariff reduction. Terms-of-trade for Korea will not change, while for Japan it will deteriorate. Equivalent variations reflecting the change in consumer surplus (welfare) will favor Korean consumers. Total output, however, will not change substantially, recording 0.5 and 0.6% for Japan and Korea, respectively. An interesting finding in the analysis is that the gains from increased competition and scale efficiency are not as prevailing as expected in theory.

• Journal of Bio-Environment Control
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• v.18 no.2
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• pp.153-159
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• 2009

This study was carried out to investigate effect of $GA_{3}$ foliar application on the growth and flowering of Limonium spp. 'Ocean Blue' to develop an effective $GA_{3}$ treatment method for a year round commercial production. Plants were treated with different concentrations of $GA_{3}$ 0, 100, 200, 400, and 800 mg.$L^{-1}$ in summer, and 0, 100,200, and 400 mg.$L^{-1}$ in winter at seven weeks after transplanting. The effects of $GA_{3}$ treatment time (0, 10, 20, 30, 40, and 50 days after planting) and plant age (raising during 3, 5, 7, and 9 weeks) was investigated. The $GA_{3}$ treatment advanced bolting and flowering with little difference between the two seasons. In a summer culture the effective concentration of $GA_{3}$ ranged from 200 to 400 mg. $L^{-1}$, while in winter it was found to be 400 mg. $L^{-1}$. The $GA_{3}$ treatment at 10 days after planting significantly reduced days to flowering. However, the greatest cut flower yield was observed in plants treated at 20 days after planting. The $GA_{3}$ treatment to different age plants did not show a significant effect, except in the oldest (nine weeks old plants). In conclusion, to induce early flowering in Limonium spp. 'Ocean Blue', the proper concentration and time of application of $GA_{3}$ was 400 mg.$L^{-1}$ $GA_{3}$ treated to nine weeks old plants at 20 days after transplanting.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.1
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• pp.50-56
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• 1994

This study was investigated for the purposes of securing forage resource using idled rice paddy recently increased in accordance to a current trend of farm products' liberalization and also of presevation of environment by using cattle sluny as liquid manure, which is seriously increasing these days. In this study, mean annual dry matter yield and its seasonal variation with reed canarygrass, and a optimum rate of cattle sluny application were investigated. The results are as follows: 1. According to the conditions of cutting frequencies(3, 4 and 5 cutting per year), mean annual dry matter yield was recorded from 8.9 tons to 10.9 tons per hectare and was the highest at 3 cutting frequency. 2. The use of cattle sluny with the levels of between 300 and 360 kg N per hectare showed a significantly higher mean annual dry matter yield than that of the control (non-fertilization). 3. The treatments with 3 and 4 cutting frequencies(90 kg Nhdyear, 120 kg Nhdyear) recorded higher dry matter yields than the control of the former level by 1.23 tons and 2.34 tons respectively and in the treatment of 5 cutting frequency, the second level with cattle sluny of 300 kg Nhdyear showed an increased dry matter yield of 2.11 tons compared to the former level(l50 kg Nhdyear). With regards to nitrogen efficiency, one kg of nitrogen is applied to 13.7, 19.4 and 14.1 kg of dry matter yields in the conditions of 3, 4 and 5 cutting frequencies respectively. 4. In view of seasonal variance of annual dry matter yield, the second cut in 3 cutting frequency, the third cut in 4 cutting frequency and the third in 5 cutting frequency showed the highest ratio as 42, 37 and 32% respectively compared to the total. 5. Under the conditions of this study, the 'Input-Output curve' from 5 cutting frequency was the closest to sigmaformed process(i=0.9993) of various cutting frequencies, and the maximum marginal yield in the treatment was obtained at the level of 250 kg Nha with cattle sluny. The economic level of cattle sluny was between 371.0 and 402.2 kg N and the highest dry matter yield was obtained at 489.3 kg Mdyear in the same treatment

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.459-468
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• 2019

Changes in growing periods and productivities of crops under double cropping of potato-rice, potato-soybean and potato-maize, were investigated at the Paddy Experimental Fields in Miryang City from 2015 to 2018. Spring potatoes planted in early March showed a yield of 2.1-2.3 ton/10a and a period of 90 days. In double cropping, growing period of rice, soybean, and maize was about 130, 125 and 115 days, respectively. The potato yield obtained was as much as 616, 330 and 815 kg/10a under double cropping with rice, soybean and maize, respectively. It is beneficial to sow the spring potatoes as early as possible to increase the yield and to secure the growing period of sequential crops. The introduction of summer medium-late variety grain crops into double cropping of spring potato and rice as well as into double cropping of spring potato and soybean/maize, was possible because of no sowing in the fall and plants were able to reach the heading growth stage before the safe heading limit of rice in particular. In the case of maize, the growth period was different according to the change in temperature over the year. The introduction of upland crops such as soybeans and maize instead of rice improved soil physicochemical properties in a short period of time, contributing to the increase of spring potato yields, but there was also a risk of damage by successive cropping for more than three years. Spring potato-maize showed higher yield in terms of starch production, and spring potato-soybean was found to be advantageous for net income.

• Korean Journal of Environmental Agriculture
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• v.34 no.3
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• pp.204-209
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• 2015

BACKGROUND: Radish (Raphanus sativus L.) is cultivated worldwide and one of important vegetables in Korea where year-round production of radish is possible. Most of radishes in autumn are cultivated with double-row spacing except for Gangwon-do where sing-row spacing is predominant. However, no research has been conducted on double-row spacing in radish cultivation so far. This study was conducted to reveal the optimum double-row spacing in autumn cultivation of radish. METHODS AND RESULTS: Using top two popular autumn radish cultivars 'S' and 'C', seeds were sown in spacing between rows of $55{\times}25$, $45{\times}25$, $35{\times}25$ and $25{\times}25cm$, and that within rows of $35{\times}28$, $35{\times}25$, $35{\times}22$ and $35{\times}19cm$. Plants were harvested 58 days after sowing and leaf weight, length and number, and root weight, length sugar content and pithiness were investigated. In the spacing between rows, no significant difference was observed in leaf weight, length and number in both cultivars; however, 25 cm of spacing between rows significantly reduced the root length and weight in 'S' and 'C' cultivars, respectively. In spacing within rows, 28, 25 and 22 cm did not affect fresh root weight in both cultivars, producing appropriate radish roots of 1,500g on average. However, 19 cm of spacing within rows did not reduced fresh root weight in 'S' cultivar but did significantly in 'C' cultivar (1148.3 g). Sugar contents and pithiness of roots were also affected by spacing but its effect was very small and different between cultivars. CONCLUSION: It is suggested that optimum double-row spacing in autumn radish cultivation is 35 cm and 22 cm of spacing between and within rows, respectively, the spacing that did not reduce the yield and quality of radish roots in two popular autumn radish cultivars.