• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.6
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• pp.251-261
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• 2022

This paper describes the finite element analysis and die design change of spring retainer forging process to reduce the cold forging load and plastic forming stress concentration. Plastic deformation analysis was carried out in order to understand the forming process of workpieces and elastic stress analysis of the die set was performed in order to get basic data for the die fatigue life estimation. Cold forging die design was set up to each process with different four types analysis progressing, the upper and lower dies shapes with combination of fillets and chamfers shapes of cold forging dies. This study suggested optimal cold forging die geometry to reduce cold forging load. The design parameters of fillets and chamfers are selected geometry were selected to apply optimization with the DoE (design of experiment) and Taguchi method. DoE and Taguchi method was performed to optimize the workpiece preform shape for spring retainer forging process, it was possible to expect an increase in cold forging die life due to the 20 percentage forging load reduction.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.147-154
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• 2022

This study was conducted by directly sowing Asemi in late April at 30 × 10 cm intervals to determine the optimal irrigation method and irrigation amount to maximize the use of limited agricultural water and to increase the yield when growing rice in a desert climate. Conventional irrigation (Conv.), surface drip irrigation (Sur), subsurface drip irrigation (Sub.), and sprinkler irrigation (Spr.) methods were used. The following amounts of irrigation were tested based on field capacity (0.33 bar): 80% (V/V, FC80), 100% (FC100), and 120% (FC120), and data for 2 years were averaged. The total amount of irrigation by irrigation method was the lowest, at 627 ton/10 a, for Sub. irrigation with the FC80 treatment, which was 60.4% less than the amount of irrigation with the FC120 treatment (1,584 ton/10a). Sub. irrigation with the FC120 treatment gave the greatest amount of rice, at 665 kg/10 a, and this condition obtained a yield of 88.1% (754 kg/10 a) of the yield obtained with the conventional treatment. Therefore, when planting rice in a desert climate, subsurface drip irrigation at 120% of field capacity is considered advantageous to increase water use efficiency and crop yield.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.653-664
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• 2021

As the construction standards for energy-saving eco-friendly housing have recently been strengthened, the proportion of window work has increased with the demand for high-efficiency housing. Windows have high frequency of use, and there is the potential for many defects to occur depending on the characteristics of construction. According to a government agency's survey of defects in public rental apartment housing, defects in the windows work accounted for the highest portion of complaints received. Accordingly, related previous studies were considered, and it was found that the existing studies in Korea lacked research that reflected the construction characteristics of window work and the importance of maintenance. In addition, existing overseas studies considered both the constructor and the resident's position, considering the cost aspect together, and showed a trend of structuring the relationship between defects and causes. Therefore, this study will analyze the causes of defects that can occur in the construction phase of the windows work, reflect the construction characteristics, and derive major factors that consider the importance of maintenance based on the possibility of recurrence after repairing defects. Ultimately, this research will contribute to preventing defects in the construction phase and reducing maintenance costs by presenting a highly effective defect management plan through selecting the major factors for each defect type that can be intuitively judged by analyzing the causal relationship between defect types and causes.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.193-206
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• 2021

Artificial Intelligence (AI) has been inserted into people's lives through Intelligent Virtual Assistants (IVA), like Alexa. Moreover, intelligent systems have expanded to design studios. This research delves into designers' perspectives on developing AI-based practices and examines the challenges of adopting future intelligent design assistants. We surveyed UX/UI professionals in Brazil to understand how they use IVAs and AI design tools. We also explored a scenario featuring the use of Alexa Sensei, a hypothetical voice-controlled AI-based design assistant mixing Alexa and Adobe Sensei characteristics. The findings indicate respondents have had limited opportunities to work with AI, but they expect intelligent systems to improve the efficiency of the design process. Further, majority of the respondents predicted that they would be able to collaborate creatively with AI design systems. Although designers anticipated challenges in natural language interaction, those who already adopted IVAs were less resistant to the idea of working with Alexa Sensei as an AI design assistant.

• Korean Journal of Construction Engineering and Management
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• v.23 no.3
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• pp.66-73
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• 2022

In order to induce users to purchase excellent products in the water industry that satisfy the technical standards of excellent products, in this study, it is to present the advantages of the cost aspect of the pumps as the objective basis. It will be to promote technology development of domestic water companies and to create a virtuous cycle structure in the water industry. In order to present an objective basis for the merits in terms of cost, an economic evaluation was conducted through life cycle cost analysis. For the LCC analysis, initial cost (pump cost and installation cost), operation cost (energy cost and maintenance cost) and demolition cost (disposal cost and residual value) are searched and calculated. As the results of comparison on two capacity of pumps, the energy cost of the excellent pump is 212 million KRW lower than the that of general pump in the large pump. The cost of excellent pump was 17 million KRW lower than that of general pump in small capacity pump. As the results of sensibility test, if the product is developed in the direction of improving pump efficiency and increasing the replacement cycle of consumables, it is predicted that the effect on LCC will be large.

• Journal of Digital Convergence
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• v.20 no.5
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• pp.463-476
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• 2022

After industrialization in the past, the automobile industry has continued to grow centered on internal combustion engines, but is facing a major change with the recent 4th industrial revolution. Most companies are preparing for the transition to electric vehicles and autonomous driving. Therefore, in this study, topic modeling was performed based on LDA algorithm by collecting 4,002 domestic papers and 68,372 overseas papers that contain keywords related to CASE (Connectivity, Autonomous, Sharing, Electrification), which represent future automobile trends. As a result of the analysis, it was found that domestic research mainly focuses on macroscopic aspects such as traffic infrastructure, urban traffic efficiency, and traffic policy. Through this, the government's technical support for MaaS (Mobility-as-a-Service) is required in the domestic shared car sector, and the need for data opening by means of transportation was presented. It is judged that these analysis results can be used as basic data for the future automobile industry.

• Journal of the Korea Institute of Building Construction
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• v.22 no.1
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• pp.91-102
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• 2022

Many industries are being severely damaged by COVID-19, a respiratory infection that has recently been prevalent around the world. In particular, for workers in the construction industry, it is impossible to work from home, and if an outbreak on a construction site is confirmed, it can lead to great damage. Accordingly, the government has drafted 「Guidelines for Response to Construction Sites for Prevention and Spread of COVID-19」. In addition, domestic and foreign research about COVID-19 in the field of construction sites is being actively conducted. However, Korea has lacked studies on the effectiveness of the countermeasures in place at construction sites, or that reflect the opinions of construction site workers. Therefore, this study conducted a survey of construction site workers by dividing the construction of the COVID-19 quarantine management system and response plan into on-site management and social management. Through the AHP/IPA analysis, it was found that among social management, 'infectious disease management system and cooperation system with related institutions' and 'reduction of working hours' are areas with high importance but low satisfaction. After that, the causes of the two items were analyzed and related countermeasures were suggested. The results of this study will be able to contribute to the improvement of the quarantine management system and response plan at construction sites, and to minimize the damage to the construction industry related to COVID-19.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.3
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• pp.311-322
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• 2022

This study performed 4-point flexural tests of reinforced concrete to which was attached a distributed optical fiber sheet and carbon fiber reinforced polymer (CFRP) sheets in order to assess the effect of the CFRP sheets and the applicability of a BOTDR sensor simultaneously. To evaluate the reinforcing effect, various degrees of CFRP sheet attachment were manufactured, and to evaluate the sensing ability, strains obtained from a BOTDR sensor were compared with strains measured from electric resistance strain gauges that were attached to the concrete surface. From the results, the reinforcing effects were evidently different according to the attachment type of the CFRP sheets, and it was confirmed that the main influencing factor on the reinforcing effect was the type of attachment rather than the attachment area. The reinforced concrete structural behavior was visualized with strains measured from the BOTDR sensor as load increased, and it was identified that load was concentrated in the CFRP reinforced area. Strains from the BOTDR sensor were similar to those from the electric resistance strain gauge; thereby a BOTDR sensor can be effective in the analysis of structural behaviorsof massive infrastructure. Finally, the strain from a BOTDR sensor was high where CFRP sheet fall-off occurs, and it would therefore be efficient to track local damage locations of CFRP sheets by utilizing a BOTDR sensor.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.77-89
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• 2022

It has been proven through many previous researches that the pretrained language model with a large corpus helps improve performance in various natural language processing tasks. However, there is a limit to building a large-capacity corpus for training in a language environment where resources are scarce. Using the Cross-lingual Post-Training (XPT) method, we analyze the method's efficiency in Korean, which is a low resource language. XPT selectively reuses the English pretrained language model parameters, which is a high resource and uses an adaptation layer to learn the relationship between the two languages. This confirmed that only a small amount of the target language dataset in the relationship extraction shows better performance than the target pretrained language model. In addition, we analyze the characteristics of each model on the Korean language model and the Korean multilingual model disclosed by domestic and foreign researchers and companies.

• The Journal of the Acoustical Society of Korea
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• v.41 no.3
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• pp.302-311
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• 2022

Sound barrier walls are one of the most effective alternatives for reducing environmental noise on roads and railways in the city center. The insertion loss of the sound barrier against road traffic noise is the sum of the sound transmission loss, sound absorption loss, and sound energy reduction due to the diffraction attenuation of the sound barrier. The sound transmission loss of the sound barrier is one of the important factors that determine the insertion loss of the sound barrier and is a basic indicator that determines the performance of the sound barrier. Nevertheless, there is not a separate standard in Korea for measuring the acoustic transmission loss of sound barrier panels. There are only a few conditions in KS F 4770 series that stipulates on the general material of sound barrier panels. This thesis examines the necessity of the acoustic transmission loss measurement and evaluation standards of sound barrier walls, and seeks a measurement method in a free sound field (anechoic chamber) sound receiving room considering the characteristics of sound barrier walls installed in external spaces, unlike indoor building materials. In addition, a single number evaluation method using a reference spectrum was proposed so that the sound insulation effect according to various installation places such as roadside or railroad side can be easily displayed.