• Journal of Drive and Control
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• v.19 no.1
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• pp.43-50
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• 2022

The aim of this study was to conduct basic research on the development of a dual-clutch transmission(DCT) and automatic transmission for agricultural tractors. The DCT layout and the DCT simulation model were developed using commercial software. Power transmission efficiency of the DCT and component power loss were analyzed to verify the developed simulation model. Power loss analysis of the components was conducted according to previous studies and ISO(International Organization for Standardization) standards. The power transmission efficiency of the DCT simulation model was 68.4-91.5% according to the gear range. The power loss in the gear, bearing, and clutch DCT system components was 0.75-1.49 kW, 0.77-2.99 kW, and 5.24-10.52 kW, respectively. The developed simulation model not include the rear axle, differential gear, final reduction gear. Therefore actual power transmission efficiency of DCT will be decreased. In a future study, an actual DCT can be developed through the simulation model in this study, and optimization design of DCT can be possible by comparing simulation results and actual vehicle test.

• Structural Engineering and Mechanics
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• v.85 no.1
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• pp.65-80
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• 2023

To explore the effect of Engineered Cementitious Composite (ECC) on improving the progressive collapse resistance of reinforced concrete frames under a middle column removal scenario, six beam-column substructures were tested by quasistatic vertical loading. Among the six specimens, four were ECC-concrete composite specimens consisting of different depth of ECC at the bottom or top of the beam and concrete in the rest of the beam, while the other two are ordinary reinforced concrete specimens with different concrete strength grades for comparison. The experimental results demonstrated that ECC-concrete composite specimens can improve the bearing capacity of a beam-column substructure at the stages of compressive arch action (CAA) and catenary action in comparison with ordinary concrete specimen. Under the same depth of ECC, the progressive collapse resistance of a specimen with ECC at the beam bottom was superior to that at the beam top. With the increase of the proportion of ECC arranged at the beam bottom, the bearing capacity of a composite substructure was increased, but the increase rate slows down with the proportion. Meanwhile, the nonlinear numerical analysis software MSC Marc was used to simulate the whole loading process of the six specimens. Theoretical formulas to calculate the capacities of ECC-concrete composite specimens at the stages of flexural action, CAA and catenary action are proposed. Based on the research results, this study suggests that ECC should be laid out at the beam bottom and the layout depth should be within 25% of the total beam depth.

• ETRI Journal
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• v.45 no.1
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• pp.171-179
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• 2023

We have developed an InAlAs/InGaAs metamorphic high electron mobility transistor device fabrication process where the gate length can be tuned within the range of 0.13㎛-0.16㎛ to suit the intended application. The core processes are a two-step electron-beam lithography process using a three-layer resist and gate recess etching process using citric acid. An electron-beam lithography process was developed to fabricate a T-shaped gate electrode with a fine gate foot and a relatively large gate head. This was realized through the use of three-layered resist and two-step electron beam exposure and development. Citric acid-based gate recess etching is a wet etching, so it is very important to secure etching uniformity and process reproducibility. The device layout was designed by considering the electrochemical reaction involved in recess etching, and a reproducible gate recess etching process was developed by finding optimized etching conditions. Using the developed gate electrode process technology, we were able to successfully manufacture various monolithic microwave integrated circuits, including low noise amplifiers that can be used in the 28 GHz to 94 GHz frequency range.

• Journal of Advanced Technology Convergence
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• v.2 no.2
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• pp.9-14
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• 2023

This study is shown the result of the first year to develop an export 1050MPa-class lightweight ductile iron castings Austempered control arm through the research process to obtain the following results. First, the structure of the optimal design Layout design and development of the component, and then achieve them through the Control Arm rigidity and optimal structure design and robust design of the focus areas of the expected stress Control Arm. Second, to develop a Control Arm reflects the high rigidity and high performance lightweight structures. Control Arm them developed to meet the design and rigidity as required by the consumer through the hollow, and to develop a process for the Core. Third, through optimum alloy composition and heat treatment methods will be derived to derive the amount of iron alloy (Cu, Ni, Mo) and Austempered heat treated and tempered condition. Fourth, through the development of optimum molding technology development component to develop the optimum ADI for the low-stiffness, high-rigidity component development, it attempts to develop a high-strength casting forming technology..

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.597-604
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• 2009

The mass transit networks in Korea, such as buses, metro and subway, are co-related and the number of transfer points, in which a lot of pedestrian movement is generated, are rising. The functions of the transfer centers, in which several travel modes cross at a point, have to include convenience and comfort for pedestrians using the transfer centers, and such functions can make transit a more attractive travel option and thus eventually contribute to increases in ridership. However, the guidelines for station layouts and their assessments in transfer stations are not suggested so far. So the pedestrian pattern data (pedestrian walking distances and times, pedestrian approaching distances and times, pedestrian walking paths in the inside of stations) was collected and analyzed. Based on the results of the analysis, the ways to measure the quality of comfort for those who using transfer facilities were suggested using the times that pedestrians consume to transfer from a travel mode to another. The walking time of pedestrians at the inside of stations was also measured by pre-selected pedestrian pathways as the guidelines for station layout assessment in transfer facilities.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.291-297
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• 2023

Objectives: An epidemiological investigation was requested for a worker who developed COPD and IPF after long-term molding and firing at a domestic tile manufacturing site. We would like to share the results of the exposure assessment and the estimation of past work. Methods: The content of crystalline silica in four raw materials was analyzed, and the respirable fraction of crystalline silica and dust generated in the air from molding and firing workers and other processes were measured. The measurement and analysis method referred to the NIOSH method. Results: The crystalline silica content of the raw material was 24~47%. The concentration of crystalline silica in the molding and firing process workers and the surrounding area was at the level of the exposure standards set by the Ministry of Employment and Labor and ACGIH, and the respirable and total dust exposure levels were generally low. The crystalline silica concentration of the area samples measured to estimate past work was about twice as high as the exposure standard of the Ministry of Employment and Labor (0.05 mg/m3), and the exposure levels of respirable dust were also quite high at 0.903 and 1.332 mg/m3. Conclusions: It was confirmed that tile molding and firing workers are currently exposed to a fairly high level of crystalline silica, and a high level is also confirmed in area samples to estimate past work. In the past, it is judged that the level of exposure would have been much higher due to differences in production volume, working method, presence/absence of local ventilation facilities, and process layout. When working in such a working environment for a long time, respiratory diseases such as lung cancer, COPD, and IPF can occur.

• Korean Journal of Agricultural Science
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• v.51 no.1
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• pp.63-77
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• 2024

Yield monitoring systems have become integral to precision agriculture, providing insights into the spatial variability of crop yield and playing an important role in modern harvesting technology. This paper aims to review current research trends in yield monitoring systems, specifically designed for non-grain crops, including cabbages, radishes, potatoes, and tomatoes. A systematic literature survey was conducted to evaluate the performance of various monitoring methods for non-grain crop yields. This study also assesses both mass- and volume-based yield monitoring systems to provide precise evaluations of agricultural productivity. Integrating load cell technology enables precise mass flow rate measurements and cumulative weighing, offering an accurate representation of crop yields, and the incorporation of image-based analysis enhances the overall system accuracy by facilitating volumetric flow rate calculations and refined volume estimations. Mass flow methods, including weighing, force impact, and radiometric approaches, have demonstrated impressive results, with some measurement error levels below 5%. Volume flow methods, including paddle wheel and optical methodologies, yielded error levels below 3%. Signal processing and correction measures also play a crucial role in achieving accurate yield estimations. Moreover, the selection of sensing approach, sensor layout, and mounting significantly influence the performance of monitoring systems for specific crops.

• Journal of the Korea Society of Computer and Information
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• v.29 no.9
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• pp.25-37
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• 2024

This study proposes a novel automation system that integrates Optical Character Recognition (OCR) and Retrieval-Augmented Generation (RAG) technologies to enhance the efficiency of the ESG (Environmental, Social, and Governance) document review process. The proposed system improves text recognition accuracy by applying an ensemble model-based image preprocessing algorithm and hybrid information extraction models in the OCR process. Additionally, the RAG pipeline optimizes information retrieval and answer generation reliability through the implementation of layout analysis algorithms, re-ranking algorithms, and ensemble retrievers. The system's performance was evaluated using certificate images from online portals and corporate internal regulations obtained from various sources, such as the company's websites. The results demonstrated an accuracy of 93.8% for certification reviews and 92.2% for company regulations reviews, indicating that the proposed system effectively supports human evaluators in the ESG assessment process.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.254-269
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• 2020

The purpose of this study is to propose guidance for wall renewal that is appropriate for an ancient city wall through application of advanced research and theories in wall design. It is a streetscape improvement project which forms part of the "Ancient City Image Finding Project". Study methods consist of advanced research classification, wall design theory contemplation, and analysis of the significance of designated ancient city areas and the "Ancient City Image Finding Project" status. Based on these methods, case study candidates were selected, case status and problems were identified, and improvement proposals were analyzed by comparing various features. Advanced wall research was classified into six categories including analysis of wall characteristics; wall design principle applications; wall structure, color, shape, and application; modern reinterpretation; palace walls; and house, temple, and village walls. The wall is an element of the streetscape improvement component of the "Ancient City Image Finding Project", with the characteristic of providing preceding experience in visual and cognitive awareness than interior structure. Case candidates for ancient city wall improvement are based on the composition distribution of the special conservation district in each ancient city as well as the conservation promotion district. Ultimately, the surrounding village of Gongju-si Geumseong-Dong Songsanri-gil, adjacent to the Royal Tomb of King Muryeong, was selected as the candidate. The "Ancient City Image Finding Project" of the surrounding village of Gongju-si Geumseong-Dong Songsanri-gil began with new Hanok construction. However, wall maintenance did not begin concurrently with that new Hanok construction. Support and maintenance took place afterwards as an exterior maintenance project for roadside structures. If the Hanok and wall were evaluated and constructed at the same time, the wall would have been built in unison with the size and design of the Hanok. The layout of the main building and wall of the Hanok is deemed to be a structure that is closed tightly because of its spatial proximity and tall height. Songsan-ri-gil's wall design should create a calm, subtle, and peaceful atmosphere with shapes, colors, and materials that express ancient city characteristics, but it is in an awkward position due to its sharpness and narrowness. The cause of the problem at Gongju-si Geumseong-dong Songsanri-gil, the case candidate, is that it is lacking significantly in terms of the aesthetic factors that traditional walls should possess. First, aesthetic consciousness seems to have disappeared during the selection and application process of the wall's natural materials. Second, the level of completion in design and harmony is absent. Maintenance guidance after analyzing the cause of problems in ancient city wall maintenance at Gongju-si Geumseong-dong Songsanri-gil, the subject area of research, is as follows: First, the Hanok design and layout of the wall and main gate should be reviewed simultaneously. Second, the one-sided use of natural stone wall in the Hanok wall design should be reexamined. Third, a permanent system to coordinate the opinions of citizens and experts during the planning and design phases should be employed. Fourth and finally, the Hanok's individuality shall be collectivized and its value as a cultural asset representing the identity of the community shall be increased.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.18 no.3
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• pp.39-50
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• 2015

This research selected Daegu Metropolitan City representing a combination of natural space and urban space for this case study. To achieve this, a prerequisite was to set up an optimal block size to evaluate landscape diversity of the research site by using a RPR-Area Curve. Further, landscape diversity evaluation was conducted based on land cover map by using FRAGSTATS to analyze spatio-temporal changes. Notably, this research regarded it as the most significant to set forth criteria in order to apply landscape diversity to the development plans of the newtown and outskirt of a city under high pressure development. Results derived from this research are summarized as follows. According to the results derived from establishing the optimal block size, a size about $2km^2$ was analyzed to measure landscape diversity of the research site. Also, according to the results derived from land diversity evaluation based on land cover map, land diversity was highly measured around urban stream such as Nakdong River and Geumho River, and in particular, the value of landscape diversity was measured considerably high around the urban parks. Results derived from analysis on spatio-temporal changes of land diversity demonstrated that a certain level of urban development exerted a positive effect on an increase in land diversity, but consistent urban development lowered a value of landscape diversity. Results derived from regression analysis to set forth the optimal urban space showed that an urban area of a space about $2km^2$ exerted a positive effect at a rate of about 0~43.3% and a negative effect at a rate about 43.3~100%. In conclusion, the results of this research are considered to provide important basic data for future urban and landscape planning. Nonetheless, as only the layout on the 2D plane was analyzed in this research, further research in future is required to complexly consider diverse factors such as height of structure and change in visible real area arising from geographical features.