• 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 the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.171-180
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• 2007

The quality of ready-mixed concrete(henceforth abbreviated remicon) is influenced by various factors such as ingredient of material, difference of property, mixing ratio, mixing time, mixing error, conditioning of construction, method of curing and temperature, humidity time in transportation. These factors make it hard to confirm the quality of remicon till placing in site. As the quality control in field is very important to ensure the quality of building. Moreover in modern building production, the more important the inquiry of performance improvement, the more important the manufacture and the quality control of remicon. In this study, to examine and analyze the quality of remicon we used slump, air content and compressive strength in 7, 28 days as to remicon which placed during on year. As a result, we found that the slump and air content were satisfied with reference code and the compressive strength was more than the design standard strength so we concluded that the quality control of remicon was to be agreeable.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.11B no.4
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• pp.151-155
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• 2001

The simple motor construction and low cost, fault tolerant power electronic drive has made the switched reluctance drive a strong contender for many applications. But the switched reluctance drive does exhibit higher levels of vibration and acoustic noise than that of most competing drives. The main source of vibration in the switched reluctance drive is generated by rapid change of radial magnetic force when phase current is extinguished during commutation action. In this paper, a hybrid excitation method is proposed to reduce vibration and acoustic noise of the switched reluctance drive. The hybrid excitation has 2-phase excitation by long dwell angle as well as conventional 1-phase excitation. The vibration and acoustic noise are reduced because the scheme reduces abrupt change of excitation level by distributed and balanced excitation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.178-183
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• 2008

본 연구에서는 대피자의 최적 배연조건 확립을 위하여 CFD모델을 이용한 수치해석을 통해 지하철 승강장 내에서의 화재 시 다양한 배연조건에서의 화재 위험성을 검토하였다. 결과로 스크린도어를 설치한 경우가 설치하지 않은 경우보다 온도의 상승폭이 최대 $65.37%{\sim}74.97%$ 낮게 나타났다. 또한 급기나 압인 배기시 승강장에 난류가 발생함에 따라 온도 및 연기층이 교란되어 하락됨에 따라 탈출시 위험을 유발할 수 있는 것으로 판단되었다. 따라서 배연용량 및 승강장 공간 설정시 배연조건에 따른 화재 특성을 고려한 설계가 필요하다.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1376-1378
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• 2002

Compare and examined Full Auto Line of PV module Manufacture Equipment and PV module Manufacture Equipment in the Korea. Full Auto Line has been constructed with Cell Selection. Tabbing & Stringing. Module Setting, Lamination, Curing and Module Testing, and Module Manufacture Line in the Korea has been constructed with Tabbing & Stringing. Module Setting, Lamination and Module Testing. Laminator's temperature Control is the most important Variable in Manufacture of PV module. Temperature Transformation of Center part of PV module is most high at Lamination, and Edge part is most low.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.1220-1222
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• 2002

The railway signaling system consists of several vital computerized equipments. Now the project for development of signaling system for the next-generation high-speed train is progressed according to the consortium. The developing signaling system by this project, kTCS(Korean Train Control System), is composed of kTCS-CTC, kTCS-IXL, kTCS-ATC and etc. The KTCS signaling has to be operated as a integrated system by interface between each signaling. To achieve these, communication protocols between each signaling have to be designed and message codes are defined. In this paper the configuration of integrated kTCS system and designed communication protocol is presented.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.43-48
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• 2003

This study presents the detailed methods for university facilities mapping using GPS and totalstation. In the control survey by GPS network adjustment, the level of significance for the height value of fourth order triangulation stations was estimated about loom. The accuracy analysis of height determination by totalstation for the traverse points showed that the RMSE came out 9mm to the basis of direct leveling, so it indicated that trigonometric leveling by totalstation was correct comparatively. For GPS/RTK method, the result of accuracy analysis about traverse points showed that the RMSE came out 33㎜ in horizontal location to the basis of totalstation's outcome and 15㎜ in height value to the basis of direct leveling. In the construction survey, GPS/RTK surveying is quicker and more economical than totalstation surveying in the feasible areas of GPS surveying, but there were many impossible areas lot GPS/RTK surveying by the obstacles like a building.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.222-224
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• 2005

In suite of their superior optical and laser properties rare-earth orthovanadate single crystals have not been adopted yet into extensive industrial applications because of crystal growth difficulties. The edge-defined film-fed-growth (EFG) technique was applied successfully for the production of such crystals. At first time 1 inch $LuVO_4$ single crystals were grown by the EFG technique using newly developed die construction of high porous iridium with the application of automatic diameter control system.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.2
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• pp.7-13
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• 2006

In this paper the noise source and the amplifying mechanism are analyzed to reduce the noise of the excavator return line using the experimental approach and the CFD simulation. The result says that the reason of noise generation is pipe vibration caused by the cavitation at the main control valve and the level of noise is proportional to the valve back pressure at the return line. The methodology to reduce this noise was proposed and verified by the vehicle test.

• Journal of Korean Academy of Nursing
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• v.39 no.6
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• pp.818-828
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• 2009

Purpose: This study was done to develop a cell phone addiction scale for Korean adolescents. Methods: The process included construction of a conceptual framework, generation of initial items, verification of content validity, selection of secondary items, preliminary study, and extraction of final items. The participants were 577 adolescents in two middle schools and three high schools. Item analysis, factor analysis, criterion related validity, and internal consistency were used to analyze the data. Results: Twenty items were selected for the final scale, and categorized into 3 factors explaining 55.45% of total variance. The factors were labeled as withdrawal/tolerance (7 items), life dysfunction (6 items), and compulsion/persistence (7 items). The scores for the scale were significantly correlated with self-control, impulsiveness, and cell phone use. Cronbach's alpha coefficient for the 20 items was .92. Scale scores identified students as cell phone addicted, heavy users, or average users. Conclusion: The above findings indicate that the cell phone addiction scale has good validity and reliability when used with Korean adolescents.