• Korean journal of applied entomology
• /
• v.43 no.4 s.137
• /
• pp.305-310
• /
• 2004

The development of Myzus persicae (Sulzer) was studied at temperatures ranging from 15 to $32.5^{\circ}C$ under $70{\pm}5\%$ RH, and a photoperiod of 16:8 (L:D). Mortality of 1st-2nd nymph was higher than that of 3rd-4th nymph at the most temperature ranges whereas at high temperature of $32.5^{\circ}C$, more 3-4nymph stage individuals died. The total developmental time ranged from 12.4 days at $15^{\circ}C$ to 4.9 days at $27.5^{\circ}C$, suggesting that higher the temperature, faster the development. However, at higher end temperature ranges of 30 and $32.5^{\circ}C$, the development took 5.0 and 6.3 days, respectively. The lower developmental threshold temperature and effective accumulative temperatures for the total immature stage were $4.9^{\circ}C$ and 116.5 day-degrees. The nonlinear shape of temperature related development was well described by the modified Sharpe and DeMichele model. When the normalized cumulative frequency distributions of developmental times for each life stage were fitted to the three-parameter Weibull function, attendance of shortened developmental times was apparent with pre-nymph, post-nymph, and total nymph stages in descending order. The coefficient of determination $r^2$ ranged between 0.87 and 0.94.

• The Korean Journal of Food And Nutrition
• /
• v.27 no.3
• /
• pp.339-347
• /
• 2014

This study investigated the classification of olive oils that are mainly distributed in Korea via imports. The fatty acid contents, degree of color, pigments, anti-oxidants, and sterol contents are analyzed on the different types of olive oil as follows: 10 kinds of extra virgin olive oil, 5 kinds of pure olive oil, and 5 kinds of refined olive-pomace oil. As a result of fatty acid analysis, the majority of oleic acid ($C_{18:1}$) and palmitic acid ($C_{16:0}$), and minority of linoleic acid ($C_{18:2}$) and stearic acid ($C_{18:0}$) were detected without any significant differences between the grades of olive oils. The UV spectrum is related to the ${\Delta}K$, and it is a part of the analysis factor for the purity and degree of degradation of the oil. Extra virgin olive oil had ${\Delta}K$ of almost 0, pure olive oil had 0.07~0.12, and refined olive-pomace oil had 0.1~0.13. These differed from extra virgin oil, and the pure or pomace oil ${\Delta}K$ had a confirmed distinct difference. The color degrees of chlorophyll with a low $L^*$ value and $(-)a^*$ (green) and carotenoid with $(+)b^*$ (yellow) were confirmed to have correlation between extra virgin and other olive oils. To compare chlorophyll and carotenoid as natural pigment in olive oils, 417 nm and the ratio of the absorbance at 480 nm (417/480) was calculated at 1.62 of extra virgin, 1.85 of pure olive oil, and 3.32 of refined olive-pomace oil. Therefore, it will be possible to distinguish when the extra virgin or pure olive oil are mixed with olive-pomace oil. The total amount of tocopherol, an anti-oxidant, were 19.06 in extra virgin, 10.91 in pure olive oil, and 27.88 in refined olive-pomace oil. The high content of tocopherol in pomace oil caused recovery of solvent extraction from olive pulp. Thus, extra virgin oil and pure olive oil were distinguished by olive-pomace oil. Polyphenol compounds in extra virgin olive oil measured high only in ferulic acid with 0.543 mg/kg, caffeic acid with 0.393 mg/kg, and other vanillic acid, vanillin, and p-coumaric acid had similar amount of 0.3 mg/kg. All grade of olive oils had the highest ${\beta}$-sitosterol content. Af (Authenticity factor) value were estimated with campesterol and stigmasterol content ratio (%). Af value was 19.2 in extra virgin olive oil, 17.1 in pure olive oil, 16.9 in refined olive-pomace oil, which were distinctive from sunflower oil with 3.7, corn oil with 2.4, and soybean oil with 2.0. It can provide important indicator of olive oil adulteration with other cheap vegetable oils. The results of this study can be used as a database for the classification of olive oil grade and distinguishing between the different types of oils.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.30 no.4
• /
• pp.329-334
• /
• 2017

The structures, which are made up with the huge number of degrees-of-freedom and the assembly of substructures, have a great complexity. In order to increase the computational efficiency, the analysis models have to be simplified. Many substructuring techniques have been developed to simplify large-scale engineering problems. The techniques are very powerful for solving nonlinear problems which require many iterative calculations. In this paper, a modal derivatives-based model order reduction method, which is able to capture the stretching-bending coupling behavior in geometrically nonlinear systems, is adopted and investigated for its performance evaluation. The quadratic terms in nonlinear beam theory, such as Green-Lagrange strains, can be explained by the modal derivatives. They can be obtained by taking the modal directional derivatives of eigenmodes and form the second order terms of modal reduction basis. The method proposed is then applied to a co-rotational finite element formulation that is well-suited for geometrically nonlinear problems. Numerical results reveal that the end-shortening effect is very important, in which a conventional modal reduction method does not work unless the full model is used. It is demonstrated that the modal derivative approach yields the best compromised result and is very promising for substructuring large-scale geometrically nonlinear problems.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.49 no.2
• /
• pp.89-100
• /
• 2021

This study evaluated the degree of interaction between the people and the environment using perceived naturalness measure. The seventh-grade index of Hemeroby was divided into subclasses of land cover according to degrees of human influence. The grade was standardized for each indicator to evaluate the current state of urban parks in Seoul by applying probability density function and weight. User evaluation was conducted on six distinctive parks selected. In the results, three implications were found between spatial evaluation according to the perceived naturalness. First, park users evaluated highly for the spaces such as broad-leaved forest, coniferous forest and mixed forest evaluated highly in the Hemeroby grade index. Park users generally recognized that various types of trees in the area had high naturalness. The density of trees is one of the factors in perceived naturalness. Second, water spaces were highly evaluated for naturalness in the Hemeroby grade index. However, the perceived naturalness of water spaces such as inland wetlands, pond and reservoir evaluated in various ways depending on environmental conditions around the park. Third, perceived naturalness is easily evaluated through vertical landscape elements such as trees rather than horizontal landscapes such as grassland. The perceived naturalness is similar to the naturalness evaluation using land cover. However the study found the perceived naturalness for a specific space was different from the Hemeroby index. Perceived naturalness by the user includes the content that the individual sees, hears, and experiences. Park users are usually structuring naturalness through evaluating the value of urban green spaces based on personal perception. Therefore there is no absolute standard criterion for evaluating the naturalness of urban green spaces. A deeper study is needed that considers user bundles or user groups with conflicting interests on the perceived naturalness in urban parks. These studies will be essential data on the direction of naturalness urban park service should provide.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.13 no.1
• /
• pp.89-100
• /
• 2010

The aim of this study is to produce land cover maps using satellite imagery with various degrees of high resolution and then compare the accuracy of the image types and categories. For the land cover map produced on a small-scale classification the estuary area around the Nakdong river, including an urban area, farming land and waters, was selected. The images were classified by analyzing the aerial photos taken from KOMPSAT2, Quickbird and IKONOS satellites, which all have a resolution of over 1m to the naked eye. Once all of the land cover maps with different images and land cover categories had been produced they were compared to each other. Results show that image accuracy from the aerial photos and Quickbird was relatively higher than with KOMPSAT2 and IKONOS. The agreement ratio for the large-scale classification across the classification methods ranged between 0.934 and 0.956 for most cases. The Kappa value ranged between 0.905 and 0.937; the agreement ratio for the middle-scale classification was 0.888~0.913 and the Kappa value was 0.872~0.901. The agreement ratio for the small-scale classification was 0.833~0.901 and the Kappa value was 0.813~0.888. In addition, in terms of the degree of confusion occurrence across the images, there was confusion on the urbanized arid areas and empty land in the large-scale classification. For the middle-scale classification, the confusion mainly occurred on the rice paddies, fields, house cultivating area and artificial grassland. For the small-scale classification, confusion mainly occurred on natural green fields, cultivating land with facilities, tideland and the surface of the sea. The findings of this study indicate that the classification of the high resolution images with the naked eye showed an agreement ratio of over 80%, which means that it can be used in practice. The findings also suggest that the use of higher resolution images can lead to increased accuracy in classification, indicating that the time when the images are taken is important in producing land cover maps.

• Korean journal of applied entomology
• /
• v.43 no.4 s.137
• /
• pp.297-304
• /
• 2004

The development of Aphidoletes aphidimyza, an aphidophagous gall midge, was studied at various constant temperatures ranging from 15 to $35^{\circ}C$, with $65{\pm}5\%$ RH, and a photo-period of 16L:8D. When A. aphidimyra was fed either on Aphis gossypii or Myzus persicae, it took 43.9 and 44.5 days, respectively, to develop from egg to pupa at $15^{\circ}C$, whereas at $25^{\circ}C$, 14.3 and 15.8 days. The developmental zero was 10.7 and $10.0^{\circ}C$, respectively, while the effective accumuative temperatures were 210.8 and 245.5 day-degrees. The nonlinear shape of temperature-dependent development, shown by A. aphidimyza when fed on either species of the aphids, was well described by the modified Sharpe and DeMichele model. When distribution model of completion time of development for each growth stage was expressed as physiological age and fitted to the Weibull fuction, the completion time of development gradually shortened from egg to larva, and to pupa. In addition, the coefficient of determination $r^2$ ranged between 0.86-0.93 and 0.85-0.94, respectively providing a good approximation of cumulative developmental rates. The life span of adult was 8.7 and 9.2 days at $15^{\circ}C$, and 3.1 and 2.7 days at $30^{\circ}C$, respectively. Egg incubation period was relatively short at $35^{\circ}C$ but hatchability was less than $50\%$ and the mortality of the larva at $35^{\circ}C$ reached $100\%$. At $30^{\circ}C$, the time of development lengthened and the adult longevity was short suggesting ill effect of high temperatures. Even though the life span of adults at $15^{\circ}C$ was relatively long, none moved freely in the rearing cage and no oviposition occurred. Accordingly, in case A. aphidimyza is adopted to suppress phytophagus aphid populations, it could be applicable to cropping systems with ambient temperatures above $20^{\circ}C$ and below $30^{\circ}C$. Within this range, A. aphidimyza adults was observed to be active and oviposit fully.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.23 no.4
• /
• pp.306-315
• /
• 2021

This study analyzed the effects of light-shielding curtains and halogens on spectrum when acquiring hyperspectral images in a greenhouse. The image data of tarp (1.4*1.4 m, 12%) with 30 degrees of angles was achieved three times with four conditions depending on 14 heights using the automatic image acquisition system installed in the greenhouse at the department of Southern Area of National Institute of Crop Science. When the image was acquired without both a light-shielding curtain and halogen lamp, there was a difference in spectral tendencies between direct light and shadow parts on the base of 550 nm. The average coefficient of variation (CV) for direct light and shadow parts was 1.8% and 4.2%, respective. The average CV value was increased to 12.5% regardless of shadows. When the image was acquired only used a halogen lamp, the average CV of the direct light and shadow parts were 2 .6% and 10.6%, and the width of change on the spectrum was increased because the amount of halogen light was changed depending on the height. In the case of shading curtains only used, the average CV was 1.6%, and the distinction between direct light and shadows disappeared. When the image was acquired using a shading curtain and halogen lamp, the average CV was increased to 10.2% because the amount of halogen light differed depending on the height. When the average CV depending on the height was calculated using halogen and light-shielding curtains, it was 1.4% at 0.1m and 1.9% at 0.2 m, 2 .6% at 0.3m, and 3.3% at 0.4m of height, respectively. When hyperspectral imagery is acquired, it is necessary to use a shading curtain to minimize the effect of shadows. Moreover, in case of supplementary lighting by using a halogen lamp, it is judged to be effective when the size of the object is less than 0.2 m and the distance between the object and the housing is kept constant.