• Journal of Drive and Control
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• v.19 no.4
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• pp.19-28
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• 2022

This paper introduces an automatic steering system for straight traveling capable of being mounted on drivable agricultural machinery which user can handle it such as a tractor, a transplant, etc. The modular automatic steering device proposed in the paper is composed of RTK GNSS, IMU, HMI, hydraulic valve, and wheel sensor. The path generation method of the automatic steering system is obtained from two location information(latitude and longitude on each point) measured by GNSS in advance. From HMI, a straight path(AB line) can be created by connecting latitude and longitude on each point and the device makes the machine able to follow the path. During traveling along the reference path, it acquires the real time position data every sample time(0.1s), compares the reference with them and calculates the lateral deviation. The values of deviation are used to control the steering angle of the machine using hydraulic valve mounted on the axle of front wheel. In this paper, Pure Pursuit algorithm is applied used in autonomous vehicles frequently. For the analysis of traveling characteristics, field tests were executed about these conditions: velocity of 2, 3, 4km/h which is applied to general agricultural work and ground surface of solid(asphalt) and weak condition(soil) such as farmland. In the case of weak ground state, two experiments were executed about no-load(without work) and load(with work such as plowing). The maximum average deviations were presented 2.44cm, 7.32cm, and 11.34cm during traveling on three ground conditions : asphalt, soil without load and with load(plowing).

• Journal of the Korean Society of Industry Convergence
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• v.25 no.3
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• pp.349-356
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• 2022

Currently, the agricultural population in Korea indicates a decreasing and aging orientation. As the population of farm labor continues to decline, so farmers are feeling the pressure to be stable crop production. To solve the problem caused by the decreasing of farm labor, it is necessary to change over to "Digital agriculture". Digital agriculture is tools that digitally collect, store, analyze, and share electronic data and/or information in agriculture, and aims to integrate the several digital technologies into crop and livestock management and other processes in agriculture fields. In addition, digital agriculture can offer the opportunity to increase crop production, save costs for farmer. Therefore, in this study, for data-based Digital Agriculture, a greenhouse environment monitoring system for crop growth monitoring based on Node-RED, which even beginners can use easily, was developed, and the implemented system was verified in a hydroponic greenhouse. Several sensors, such as temperature, humidity, atmospheric pressure, CO₂, solar radiation, were used to obtain the environmental data of the greenhouse. And the environmental data were processed and visualized using Node-RED and MariaDB installed in rule.box digital. The environment monitoring system proposed in this study was installed in a hydroponic greenhouse and obtained the environmental data for almost two weeks. As a result, it was confirmed that all environmental data were obtained without data loss from sensors. In addition, the dashboard provides the names of installed sensors, real time environmental data, and changes in the last three days for each environmental data. Therefore, it is considered that farmers will be able to easily monitor the greenhouse environment using the developed system in this study.

• Journal of Drive and Control
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• v.20 no.4
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• pp.27-34
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• 2023

Weeding in orchards is closely associated with productivity and quality. The customary weeding process is both labor-intensive and time-consuming. To solve the problems, there is need for automation of agricultural robots and machines in the agricultural field. On the other hand, orchards have complicated working areas due to narrow spaces between trees and amorphous terrain. Therefore, it is necessary to develop customized robot technology for unmanned weeding work within the department. This study developed a path generation and path control method for unmanned weeding according to the orchard environment. For this, the width of the weeding span, the number of operations, and the width of the weeding robot were used as input parameters for the orchard environment parameters. To generate a weeding path, a weeding robot was operated remotely to obtain GNSS-based location data along the superheated center line, and a driving performance test was performed based on the generated path. From the results of orchard field tests, the RMSE in weeding period sections was measured at 0.029 m, with a maximum error of 0.15 m. In the steering period within row and steering to the next row sections, the RMSE was 0.124 m, and 0.047 m, respectively.

• Journal of Environmental Impact Assessment
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• v.7 no.1
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• pp.35-48
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• 1998

Gaussian type models have limitations on predicting a detailed description of the near flow and pollution leads over complex terrains under neutral atmospheric conditions. Also, most models used recently have lack of ability to include atmospheric reactions. The model based on the numerical solution of the time-averaged Navier-Stokes equations and conservation equations needs to be developed to improve the limitations mentioned above. When the model was applied to the Shihwa area where the tracer experiment had been carried out, the simulation results have a great difference from the experimental results. There are two reasons that make the difference between the results by the model and the experiment. First, the Shihwa area is not a complex terrain. Second, meteorological data is insufficient. Therefore, the model should be applied to predict the dispersion of air pollutants over complex terrain rather than flat terrain in order that the model could be verified because the model was developed for the prediction of the dispersion over a complex terrain.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.167-170
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• 2000

Proteolytic hydrolysis is one of the main enzymatic reaction of waste activated sludge (WAS) digestion. Pretense excreted from Bacillus stearothermophilus (ATCC 31197) showed optimum temperature of $75^{\circ}C$ for maxium heat stable proteolytic activity against azo casein. The dependency of $Ca^{2+}$, $Zn^{2+}$ on heat stability of proteolytic enzymes were measured with various concentrations. It was shown that $Ca^{2+}$ ion enhanced heat stability of these enzymes. Then thermophilic aerobic digestion (TAD) was performed using B. sterothermophilus with the addition of divalent ions. Performance of TAD process with ATCC 31197 activated by $Ca^{2+}$, $Zn^{2+}$ions in terms of dissolved organic carbon (DOC) concentration, extracellular protein concentration, and scanning electrion microscopy (SEM) analysis. The best result of protein reduction concentration in digestion test was obtained with the addition of 2 mM $Ca^{2+}$ ion.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1585-1587
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• 2001

ac PDP 동작에 있어 미량 불순물 가스는 panel 내의 휘도 및 방전 특성에 많은 영향을 미칠것으로 생각된다. $O_2$, O, C 및 $H_2$와 같은 불순물 가스는 ac PDP의 제조 공정 중에 발생하거나, 충전된 방전가스에 혼합되어 발생하는 등 여러 가지 원인으로 나타난다. 이 논문에서는, ac PDP의 동작 가스 중에 미량의 불순물 가스(Ar, $N_2$, $O_2$, $H_2$, $CO_2$)를 주입하여, 이 미량의 불순물 가스로 인한 ac PDP의 휘도 및 방전의 특성변화에 대한 관계를 조사하였다. 그 결과, $O_2$ 가스의 분압이 $2{\times}10^{-3}$/He+Ne+Xe(4%)일 경우, 방전전압은 12% 증가하였고, 휘도는 60% 감소하였다. 또한, $CO_2$ 가스의 경우는 방전전압은 14% 증가하였고, 휘도는 44% 감소하였다.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1588-1590
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• 2001

The voltage controlled ramp waveform(VCR) has recently been used in the reset period prior to addressing for plasma display. However, in this paper, the current controlled ramp waveform(CCR) which may prevent the oscillation of gap voltage cause current growth and decrease the background luminance has been suggested. As a result, in case of CCR method, the contrast ratio was about 14% increased compared with VCR method, whereas the addressing and sustainin discharge characteristics of CCR method were same with those of VCR method.

• Tuberculosis and Respiratory Diseases
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• v.59 no.3
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• pp.311-314
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• 2005

Pulmonary aspergillosis may present with three different features, according to the immune status of the host. These forms are invasive aspergillosis, allergic bronchopulmonary aspergillosis (ABPA) or aspergilloma. Bronchial involvement is an uncommon type of invasive pulmonary aspergillosis. We encountered an unusual case of an endobronchial aspergillosis that completely obstructed the left upper lobe, which was initially thought to be lung cancer. We report this case along with a review of the relevant literature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.153-157
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• 2002

This paper deals with the relationships between MgO manufacturing condition and misfiring at low temperature. The characteristics of MgO are affected by substrate temperature and MgO deposition current. In this study. the. substrate temperature was varied from $100^{\circ}C$ to $200^{\circ}C$. And the MgO deposition current was varied from 5mA to 20mA. As a result. the misfiring at low temperature was decreased in the panels with substrate temperature $200^{\circ}C$ and MgO deposition current 5mA. These results may be explained that the higher substrate temperature and lower MgO deposition current makes the denser film formation.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.265-270
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• 2009

In October 2009, hunting billbug, Sphenophorus venatus vestitus Chittenden, was first found on zoysiagrass at Yongweon country club in Jinhae. The adult was 6~11mm long and dark brown to black color. The pronotum is coarsely punctate except for a "Y"-shaped area in the center and a parenthesis-like marking on each side. This pattern is characteristic of the species. This billbug feeds on warm-season grasses like zoysiagrass and Burmudagrass. As the hunting billbug is one of the plant quarantine pests in Korea, the National Plant Quarantine Service surveyed additional occurrence for neighboring golf courses and some turfgrass farms, but not found yet.