• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.5
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• pp.737-742
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• 2009

The popularity of autonomous mobile robots have been rapidly increasing due to their new emerging application area, from room cleaning, tourist guidance to space explorations. However, the development of a satisfactory control algorithm that will enable the autonomous mobile robots to navigate safely especially in dynamic environments is still an open research problem. In this paper, a newly proposed potential field based control method is implemented, analyzed, and improvements are suggest based on experimental results obtain from computer simulations. The experimental results are presented to show the effectiveness of the behavior-based control using the proposed potential field generation technique.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.3
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• pp.155-162
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• 2014

This study was conducted to investigate the influence of the mixed application of chemical fertilizer (CF) and liquid swine manure (LSM) on the agronomic characteristics, dry matter yield, amino acids, minerals, and free sugars in cultivating Sorghum ${\times}$ Sudangrass hybrid (SSH) on paddy soil. The field experiment was designed in a randomized block design with three replications and consisted of CF 100% (C), CF 70% + LSM 30% (T1), CF 50% + LSM 50% (T2), CF 30% + LSM 70% (T3), and LSM 100% treatment (T4). The application of LSM was based solely on the nitrogen. Plant length, leaf length, leaf width and number of leaf were significantly higher in T4 (p<0.05), but stem diameter did not show significant differences among treatments. Stem hardness increased significantly (p<0.05) as the LSM application rate decreased, but sugar degree decreased significantly (p<0.05) as the LSM application rate decreased. Fresh yield, dry matter yield and TDN yield were the highest in T4, whereas the lowest in T2 (p<0.05). Crude protein, crude fat and crude ash were the highest in C, T4 and T2, respectively (p<0.05). However, NDF and ADF did not show significant difference among treatments. Crude fiber decreased significantly (p<0.05) as the LSM application rate increased. The total mineral content was decreased significantly (p<0.05) as the LSM application rate increased. Total amino acid content was higher in the order of T1> C> T3> T4> T2 (p<0.05). Free sugar content increased significantly (p<0.05) as the LSM application rate increased. The analysis of all the above results suggests that the application of liquid swine manure is very effective, considering the yield performance and the content of sugar degree and free sugar. In addition, liquid swine manure may be possible to grow Sorghum ${\times}$ Sudangrass hybrid without chemical fertilizer.

• Journal of Radiation Industry
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• v.9 no.1
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• pp.21-27
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• 2015

The domestic Radiation Technology is integrated into and utilized in various areas and is closely related to the industrial growth in Korea. The domestic use of radiation and RI (Radioisotope) increases in quantity every year, however the level of technology is poor when compared to other developed countries. Manpower training is essential for the development of Radiation Technology. Therefore, this study aimed to propose a methodology for designing systemic education and training model in the field of measurement and analysis of radiation. A survey was conducted to design education and training model and the training program for measurement and analysis of radiation was developed based on the survey results. The education and training program designed in this study will be utilized as a model for evaluating the professional development and effective recruitment of the professional workforce, and can be further applied to other radiation-related fields.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.42-54
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• 2001

The use of nitrogen fertilizer in intensive agricultural production is of major concern due to its role on agricultural productivity and water quality. Crop production inputs on farm are usually applied at a uniform rate across an entire field. However, actual input requirements often vary within fields. The field variations in yield potential, soil moisture, soil N status, and the efficiency of fertilizer use, uniform application of crop production inputs does not allow optimum efficiency or profitability. This occurs because uniform application often results in areas of over- and under-application which may affect water quality and crop yield. This study used biophysical and economic models to assess the economic feasibility and water quality benefits of site specific nitrogen management for 10 soil types and 35 sample fields in Goodwater Creek watershed located near Centralia, Missouri. Results showed that the economic feasibility and water quality benefits of variable rate application were sensitive to the distribution of soil types within a field. Variable rate(VR) application was not uniformly more profitable than uniform rate(UR) application for the four agricultural systems evaluated and the water quality benefits were insubstantial relative to uniform application of N.

• Journal of Environmental Science International
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• v.4 no.2
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• pp.169-180
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• 1995

This Daper presents effective simulation of the dispersion of thermal discharge which can be relesed at Boryong power plant. Applied numerical models are finite difference method for hydrodynamic analysis and Masch-model comprised of conditions for ambient current velocity. Application of these models is done in Cheonsu Bay Summing up the results of this study are as follows; 1. It is found that the result for measurements of temperature appears high at southwardly Songdo on flood. The reason is that tidal currents which flowed north direction were accompanied with southwardly dispersed thermal discharge. A minute Particle of thermal Plume has a tendency to dispels inward Deacheon Bay. 2. According to the results of numerical experiment, maximum distance for thermal discharge dispersion appeared 10.8 km at lower part and 8.6 km at upper part with power plant outlet as starting point. 3. Comparative the numerical simulation and Airbone Multispectral Scanner indicated that thermal discharge should be verified separative phenomena. The simulated results were compared with field data set showing good agreement. It is concluded that these model can be simulated well.

• Journal of the Society of Disaster Information
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• v.9 no.2
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• pp.206-213
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• 2013

The paper presents the field applications and evaluation results of solid epoxy asphalt mixture for steel bridge deck. The material was developed in Japan. The material properties of epoxy asphalt mixture were evaluated through various literature review, and the mix design and mixture evaluation were conducted. According to the research results, the application of epoxy asphalt mixture for steel bridge deck was noticeable compare to the conventional ones. In addition, results from 3D finite element analysis showed that the performance of epoxy asphalt mixture for steel bridge deck was proved to be satisfied. As a result, a pilot test section was constructed using the epoxy asphalt mixture produced from conventional batch plant system. BPT test results showed that friction of the epoxy asphalt mixture was higher than the requirements compare to that of the conventional one.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.33-39
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• 2021

BACKGROUND: Globally, large amounts of phosphogypsum (PG), which is a by-product of the phosphate fertilizer production, is deposited in open areas. As PG contains calcium, phosphate, and sulphate, it can be used as a soil amendment in farmlands. This study was conducted to investigate the effects of PG application on properties of field soil and yield and quality of garlic (Allium sativum L.), and to seek appropriate level of PG application into the field. METHODS AND RESULTS: This experiment was conducted by applying PG at four different levels that were adjusted based on 65% calcium base saturation in the field soil: 0% (control), 50% (PG50, 100 kg/10a), 100% (PG100, 200 kg/10a), and 150% (PG150, 300 kg/10a). Following cultivation, soil electrical conductivity (EC), organic matter, available P and exchangeable Ca increased, whilst soil pH decreased. With increase in PG application level, soil EC and exchangeable Ca increased. PG application increased concentrations of water soluble Ca and SO4 across the soil profile, especially in PG150. The highest yield of garlic was found in PG100 treatment. The plant's uptake for N, P, Ca, and S increased by PG applications, but that for K decreased. Moreover, concentrations of S-related amino acids such as cysteine and methionine in garlic increased by PG applications. The increased content of nutrients and amino acids with PG supply might improve yield, quality, and favor of the crop. CONCLUSION: Overall, PG application at 200 kg/10a into a field had the best effect on improving soil fertility as well as yield and quality of garlic. Further studies are required to maximize efficiencies of PG supply in soil management and production of various crops.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.457-467
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• 2010

The settlement prediction is very important to preloading method for a construction site on a soft ground. At the design stage, however, it is hard to predict the settlement exactly due to limitations of the site survey. Most of the settlement prediction is performed by a regression settlement curve based on the field data during a construction. In Korea, hyperbolic method has been most commonly used to align the settlement curve with the field data, because of its simplicity and many application cases. The results from hyperbolic method, however, may be differed by data selections or data fitting methods. In this study, the analyses using hyperbolic method were performed about the field data of $\bigcirc\bigcirc$ site in Pusan. Two data fitting methods, using an axis transformation or an alternative method, were applied with the various data group. If data was used only after the ground water level being stabilized, fitting results using both methods were in good agreement with the measured data. Without the information about the ground water level, the alternative method gives better results with the field data than the method using an axis transformation.

• International Journal of Highway Engineering
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• v.18 no.3
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• pp.67-74
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• 2016

PURPOSES : This study evaluated the field applicability and laboratory performance of glass fiber-reinforced asphalt (GFRA) mixtures. METHODS : The general hot-mix asphalt (HMA) and GFRA mixtures were paved in five sites, including three national highways, one express highway, and an arterial road, to evaluate field applicability and durability. The plant mixing and construction method for the GFRA were similar to those for the general HMA. The lab performances of the field samples were relatively compared through the mechanical measures from the Marshall stability, indirect tensile strength, and dynamic stability. The field performance was surveyed after a year. RESULTS : The lab tests verified the superior lab performances of the GFRA compared to the general HMA. The Marshall stability of the GFRA increased for about 128% of the general HMA. The indirect tensile strength of the GFRA was 115% greater than that of the general HMA. The dynamic stability of the GFRA resulted in 16,180 reps/mm, which indicated that high rut resistance may be expected. No noticeable defects, such as cracks or deformation, were observed for the GFRA sections after a year. CONCLUSIONS : The lab tests and field survey for the five GFRA sites resulted in superior performances compared to the general HMA. The relatively low-cost GFRA, which required no pre-processing procedures, such as polymer modification, may be a promising alternative to the polymer-modified asphalt mixtures. The long-term performance will be verified by the superior field durability of the GFRA in the near future.

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.9-18
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• 2012

PURPOSES : This study evaluated the field applicability and laboratory performance of warm-mix asphalt (WMA) as an alternative technology in asphalt pavement. METHODS : The pilot road using two different types of WMA mixture and one HMA mixture was constructed in Waegwan-Seokjeok road construction site and the mixtures were sampled at the asphalt plant for laboratory testings. The field applicability was assessed in environmental aspects, such as $CO_2$ emission, and in aspects of constructibility using the existing equipment and procedure, i.e., thickness and density measurement. The laboratory testings included the moisture susceptibility test by AASHTO T283, dynamic modulus test, triaxial repeated load permanent deformation test, and the fatigue test. RESULTS : The temperatures for production and compaction of WMA were $20{\sim}30^{\circ}C$ lower than those for HMA and therefore, the noxious gas emission were significantly reduced. The field density of WMA pavements was similar or better than that of HMA pavement. From the laboratory testings, it was found that WMA mixtures exhibit comparable performance to HMA mixture in moisture susceptibility, permanent deformation, and fatigue performance. CONCLUSIONS : With these results, it would be concluded that WMA could replace the existing HMA technology without any significant issue. To support this conclusion, it is necessary to track the long-term performance of WMA in pilot road.