• Korean Journal of Optics and Photonics
• /
• v.26 no.3
• /
• pp.155-161
• /
• 2015

We report the design and performance analysis of an off-axis three-mirror telescope as the fore optics for a new hyperspectral sensor aboard a small unmanned aerial vehicle (UAV), for low-altitude coastal remote sensing. The sensor needs to have at least 4 cm of spatial resolution at an operating altitude of 500 m, $4^{\circ}$ field of view (FOV), and a signal to noise ratio (SNR) of 100 at 660 nm. For these performance requirements, the sensor's optical design has an entrance pupil diameter of 70 mm and an F-ratio of 5.0. The fore optics is a three-mirror system, including aspheric primary and secondary mirrors. The optical performance is expected to reach $1/15{\lambda}$ in RMS wavefront error and 0.75 in MTF value at 660 nm. Considering the manufacturing and assembling phase, we determined the alignment compensation due to the tertiary mirror from the sensitivity, and derived the tilt-tolerance range to be 0.17 mrad. The off-axis three-mirror telescope, which has better performance than the fore optics of other hyperspectral sensors and is fitted for a small UAV, will contribute to ocean remote-sensing research.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.2
• /
• pp.31-34
• /
• 2009

Purpose: We are to analyze optically how to affect the eye related with movement of the iris. Methods: Using the schematic eye to have the crystalline lens of the radial GRIN and the spherical GRIN forms that come to be planned in existing, the iris centre was moved 0.5 mm with nasal direction in order to be identical with the real eye. Also, considering that the iris centre move according to increase of the pupil size, the iris centre was moved 0.4 mm with temporal direction to analyze the optical performance change of the eye respectively. Results: Because of decrease in the spherical aberration, the schematic eye with nasal direction 0.5 mm eccentricity of the iris showed a different consequence plentifully compared with the performance of the real eye. Besides, the schematic eye with temporal direction 0.4 mm eccentricity of the iris showed that the spherical aberration somewhat increased. Conclusions: In case of design of the schematic eye with the similar real eye performance which the iris centre was moved 0.5 mm with nasal direction, we need to research about aspheric coefficient of optical constants of each refracting surface considering the performance change of a spherical aberration, a peripheral power error and astigmatism etc, owing to change of the real eye hence to be affected by the iris movement.

• Journal of Korea Water Resources Association
• /
• v.44 no.10
• /
• pp.819-830
• /
• 2011

The multi-slope MUSCL, proposed by T. Buffard and S. Clain, determines slopes of conserved variables at each edge of a cell in the linear reconstructions of data. In this study, the second order accurate numerical model was developed according to the multi-slope MUSCL to solve the shallow water equations on the unstructured grids. The HLLL scheme of approximate Riemann solvers was used to calculate fluxes. For the review of the applicability of the developed model, the results of the model were compared to the 'isolated building test' and the 'model city flooding experiment' conducted as part of the IMPACT (Investigation of extreMe flood Processes And unCerTainty) project in Europe. There were limitations to predict abrupt rising of water depths by the resistance of model buildings and water depths at the specific locations among the buildings. But they were identified as the same problems also revealed in results of the other models to the same experiment. On the more refined meshes to the 'model city flooding experiment' simulated results showed good agreement with measurements. It was verified that the developed model simulated well the complex phenomena such as a dam-break problem and the urban inundation by flash floods.

• Journal of Korean Society of Forest Science
• /
• v.56 no.1
• /
• pp.51-65
• /
• 1982

The growth characteristics and appropriate fertilizer-managements in the rejuvenating bamboo grove were studied with Phyllostachys reticulata. The bamboo soil was the sandy loam with rich humus. In the fertilized plots, the N-fertilizer was significantly absorbed, and it was necessary to fertilize the K-fertilizer continuously. According to the development of rejuvenating after flowering, the temperature and relative illumination became lower. while the moisture became higher. The relationship between the diameter at eye height (D) and the culm length (H) of each bamboo can be expressed as follow; $H=2.5538D^{0.5031}$ The leaf area is the major factor for the production of the bamboo grove. Therefore in the rejuvenating grove, we should refrain form pruning or felling of not -flowering bamboo. The theoretical distribution of the internodal length was obtained by the distribution curve line of the internodal length derived from the regular distribution curve line. Relatively long and even internodal length was found in the fertilized plots 2 and 4. The relation between $D^2H$ and dry weight of culm or dry weight of the above ground part were given by linear regression in both relations respectively on the logarithmic coordinates, but the propertional relation was not established in these relations. The biomass of the above ground part obtained by the allometry method showed high values in the fertilized plots 2.5 and 6. The appropriate amounts of the three elements, N, P and K for the maximum dry matter were 24.19, 15.51, 8.63 kg/10a, respectively.

• Korean Journal of Agricultural Science
• /
• v.13 no.1
• /
• pp.33-43
• /
• 1986

Long-term fertilizer application have been carried out at experimental farm of the Yeongnam Crop Experiment Station from 1967 to 1983 to obtain basic informations about longterm effect of fertilizer regime, especially, compost and chemical fertilizer on the soil chemical properties and the rice growth. 1. Rice yields obtained from the non-fertilized plot and PK applied plot were significantly reduced compared to NPK applied plot by 43% and 53%, respectively, primarily due to decrease of leaf area, crop growth rate, number of panicles and number of spikelets and delayed flowering. 2. No visible phosphorus-symptom and yield loss were obserbed at the plot that phosphorus was not included even though phosphorus content in the soil and rice plant were lowered. 3. The plot that was not received potassium resulted in yield loss by 9% compared to NPK applied plot due to decrease in potassium content in soil and rice plant, and spikelt number. 4. Available phosphorus, silica, and exchangeable potassium in soil significantly increased by adding compost to NPK applied plot and hence, increased grin yield by 6 to 9% compared to applied plot through improvement of nutrient uptake efficiency. 5. Grain yield of compost applied plot lowered by 30% than NPK applied plot due to decreased nutrient uptake efficiency and delayed rice growth while this yield was higher than Non-fertilized plot.

• Journal of The Korean Association of Information Education
• /
• v.20 no.5
• /
• pp.465-474
• /
• 2016

The present study is aimed to find the effect of the activity of writing a structured reflection journal in the learning process of PBL-based programming on the logical thinking of elementary school students. To achieve the objective, this study carried out an experiment with 59 elementary school students in the 5th grade. They were divided into an experimental group and a control group. The experimental group was applied with PBL-based programming classes by learning step, including learning of the contents, its procedure, and the activities of writing a critical reflection journal while the control group received learning of PBL-based programming including unstructured reflection journal. And then the difference in their logical thinking was compared and analyzed before and after th experiment. The results demonstrated that the experimental group showed a significant difference in logical thinking before and after writing structured reflection journal (ANCOVA) at the significance level of .05, which evidenced writing a structured reflection journal has learning effect. Intergroup comparison of logical thinking also showed that there was learning effect. Those findings suggest that writing a structured reflection journal in the PBL-based programming learning for 5th grade elementary school students has a positive effect on the learners' logical thinking.

• Korean Journal of Soil Science and Fertilizer
• /
• v.27 no.2
• /
• pp.78-84
• /
• 1994

Yield response of tomato to nitrogen and potassium fertilizer and the balance of the two elements were determined in salt-accumulated greenhouse soil to improve the efficiency of fertilizer appiication. The response of tomato yield to nitrogen and potassium fertilizer application was not significant. The current parameters such as OM and $K/{\sqrt{Ca+Mg}}$ that were used to determine the level of nitrogen and potassium fertilizer in open field were not suitable in salt-accumulated greenhouse soil condition. The temporal and spatial distribution of $NO_3{^-}-N$showed the same pattern to those of $Cl^-$ ion that is non-reactive with soil, while the content of Ex. K was extraordinarily high in soil after harvesting of tomato, which had experienced relatively dry condition during harvesting time. The loss of $NO_3{^-}-N$ and Ex. K out of 28cm below the soil surface was 2~5 and 1.5~3.5 times greater than the amount of nitrogen and potassium uptake by the plant.

• Journal of Animal Environmental Science
• /
• v.10 no.2
• /
• pp.75-80
• /
• 2004

Field experiments were conducted in 2002 on sandy loam soil under variable fertilizer management; swine slurry and chemical fertilizer. The effect of different fertilizer management and application method on the growth characteristics and yield of rice were determined. The rice was planted to examine the effect of swine slurry on the crop growth. As slurry manure was fertilized, yield of each group of rice was decreased from 3 to $5\%$. In conclusion, basal application of slurry was maintained productivity of rice, but to improve of productivity of rice, the rice should be fertilized with the basal application of animal slurry and supplementary application of chemical fertilizer. The results indicates that application of animal slurry improves quality of rice rather quantity, which means grain yield. Rice quality of the slurry+chemical and the slurry were significantly better than that of the chemical fertilizer. That indicates application of animal slurry could improve rice quality. Application of animal slurry seemingly has potentials for reducing pollution of animal slurry and improving environment of rural area as well as producing high-quality rice.

• Journal of Animal Environmental Science
• /
• v.13 no.2
• /
• pp.139-146
• /
• 2007

Field experiment was conducted to assess the influence of liquid compost supplemented with chemical fertilizer on the rice growth and yield in 2005. Treatments consisted of liquid compost supplemented with chemical fertilize.(LCSC), liquid manure(LM), chemical fertilizer(CF), LCSC 50% + 50%CF, LCSC 75% + 25%CF. The plant height and tiller's number in plots of 100% basal application plot by LCSC and LM plot were lower than that of chemical fertilizer. But in the plot of basal application by LCSC and top dressing by chemical fertilizer, the height and tilters of rice were significantly difference with LM application plot. And the leaf color the plots by LCSC and chemical fertilizer was darker than that of the LM application plot. In plots by LCSC treatment, number of panicles per hill was higher that of LM plot. As the plot of 100% basal application by LCSC was fertilized, the yield of rice was decreased compared with chemical fertilizer. But the rice yield of basal fertilization by LCSC and top-dressing by chemical fertilizer was 7% increased compared with LM plot. The application plots by LCSC + chemical fertilizer plot were maintained productivity of rice, the rice should be fertilized with the basal application of LCSC and top-dressing of chemical fertilizer. The quality of brown rice was best in LM and LCSC plot, whereas in chemical fertilizer plot, it was the worst by increased of protein content. The results indicates that the application of LCSC + chemical fertilizer improves quality of rice rather quantity.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.24 no.3
• /
• pp.35-42
• /
• 1979

Experiments were conducted to find out the labor saving efficiency and optimum seeding rate and fertilizer level when newly invented Barley Rotor Caster was used in wheat sowing on paddy field. It decreased the labor for sowing by 66~77% compared with conventional sowing method. And the optimum. seeding rate was considered to be approximately 20$\ell$Q per 10a in standard fertilizer level and optimum fertilizer level to be 18-12-12kg/10a, $N-P_2O_5-K_2O$ respectively.