• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.56-65
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• 2019

Recently, automobiles have been developed for safety and environmental reasons. Particularly, awareness of automobile safety is changing significantly. As a result, safety systems developed by ADAS have emerged. However, the period of mass production through ADAS development and test evaluation is long. Therefore, in this paper, we develop a brake dynamometer to shorten the time required for ADAS development and test evaluation. In addition, the developed brake dynamometer satisfies the international standard JIS D-0210, and the user can evaluate the braking force by selecting test conditions and test method for each mode of ADAS. We use the ACC, LKAS, and AEB scenarios proposed in previous studies to verify the reliability of the developed brake dynamometer. The developed brake dynamometer was verified by comparing the test values and the calculated values using theoretical formulas of the proposed ADAS mode based on previous studies. In addition, it is expected that the performance evaluation of brake parts for each ADAS mode will be possible in an environment where the vehicle test of ADAS is not possible in the future.

• Journal of the Korea Safety Management & Science
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• v.21 no.1
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• pp.1-7
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• 2019

Along with industrial development, various architectural structures have become bigger and higher, leading to an expansion in the size and capacity of construction equipment. And with the development of public transportation, the use of subways as a means of transportation in the city center is increasing, so that vibrations and structural noises are emerging as a new environmental issue. Considering that architectural structures may be used from several decades to hundreds of years after the time of construction, they can be seen as semi-permanent. Due to changes in the vibration-proof polyurethane mats installed in the foundation of these structures, settling may occur and vibration reduction may become inadequate. Therefore, in view of service life, it is necessary to have a high-level standard of reliability and stability. In accordance with this, the Floating Floor System, which uses soft polyurethane foam and can be constructed within a relatively short period of time, has excellent vibration resistant characteristics. It is presented as a great alternative solution to the issue of vibrations caused by subways, railways and building structures. At present, vibration-proof polyurethane mats have been developed up to the same product level as in other advanced countries. However, in the construction of structure foundations, the physical properties of this product and its shape incur changes. If they are installed as such in the structure of a building, it may cause significant impact on stability, requiring that this cause be urgently identified and improved.

• Journal of Korean Elementary Science Education
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• v.38 no.2
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• pp.173-190
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• 2019

The self-efficacy of pre-service teachers has been reported as a major factor in the instruction of the curriculum. In particular, considering the importance of science learning instruction for underrepresented students from the viewpoint of science education for all, pre-service elementary teachers' self-efficacy about science instruction for underrepresented students will be an important factor of science education for these students. The purpose of this study is to investigate the self-efficacy of pre-service elementary teachers in science instruction for underrepresented students. To this end, the science teaching and learning self-efficacy test tool (Lee & Im, 2010) was revised in accordance with the context of science teaching for underrepresented students into a total of 24 items using 5 Likert scales. Through using the test tool consists of 3 dimensions as Learning Efficacy, Teaching Efficacy and Outcome Expectancy, 81 pre-service elementary teachers were surveyed and the reliability of test tool was verified through factor analysis and assessing construct validity by using the responses. As a result of the analysis, setting 5 as the standard perfect score, the average score of self-efficacy per dimension was shown as 3.29 in Learning Efficacy, 2.89 in Teaching Efficacy, and 3.39 in Outcome Expectancy. We confirmed the tendency and difference of self-efficacy of the research objects according to their background factors in which direct and indirect experience relating to the science education for the underrepresented students. Also, we verified that pre-service elementary teachers' interest in science subject matter, teaching science and their perception of the value of science learning had significant relations with self-efficacy on science teaching for underrepresented students.

• Journal of the Korea Convergence Society
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• v.10 no.5
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• pp.323-331
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• 2019

The purpose of this study is to investigate the relationship between exercise participation attitude, self- esteem and achievement goal orientation of college students majoring physical education. In order to achieve the purpose of study, a survey was conducted with 385 college students majoring physical, and the data collected from the survey were processed for frequency analysis, exploratory factor analysis, reliability analysis, correlation analysis, and standard multiple regression analysis using SPSS Version. 15.0. The following results were drawn from these analyses. First, it was found that all the sub-variables between exercise participation attitude and self-esteem of college students majoring physical education are related. Second, it was found that all the sub-variables between exercise participation attitude and achievement goal orientation of college students majoring physical education are related. Third, it was found that all the sub-variables between self-esteem and achievement goal orientation of college students majoring in physical education are related.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.51-63
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• 2021

Recently, virtual communication has become a standard tool due to the outbreak of COVID-19. Likewise online communication is emerging as an essential competency. In this study, we aimed to develop a comprehensive and systematic digital literacy measurement tool reflecting the changes and needs of society. Construct variables were drawn by characterizing existing digital literacy measurement tools. Thirty-four items corresponding to the concept of each variable were developed. The developed measurement tool was then evaluated in the form of surveys from university students belonging to the digital native generation, and the reliability and validity were performed through exploratory and confirmatory factor analysis. The digital literacy measurement tool contained five sub-factors and twenty-five questions. In addition, hierarchical regression analysis was performed to verify the predictive validity of digital literacy sub-factors. Based on these findings, the implication of future research is discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.205-210
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• 2019

In this study, in order to promote informatization of Meat Processed Food Industry, we standardize three processes of sales management, purchaser logistics and production management, develop standard modules, and develop integrated business functional design in ERP system development. This study reduces the cost of introducing the production equipment information standardization module in the food industry and the specialized IT companies that are slow in informatization, and maximizes the effectiveness and provides reliability by being a database where research standardization can be compared and analyzed. By applying the results of this study, it is possible to establish efficient processes of sales, buyer logistics, production, improvement of quality, and reduction of production cost from the receipt of food raw materials / subsidiary materials to finished products.

• International journal of advanced smart convergence
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• v.8 no.2
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• pp.109-115
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• 2019

Currently, LPWA(Low Power Wide Area) communication technology is widely used due to the development of IoT(Internet of Things) technology. Among the LPWA technologies, LoRaWAN(Long Range Wide Area Network) is widely used in many fields due to its wide coverage, stable communication speed, and low-cost modem module prices. In particular, LoRa(Long Range) can easily construct LoRaWAN with a dedicated gateway. So many organizations are building their own LoRaWAN-based networks. The LoRaWAN Gateway receives the LoRa packet transmitted from an End-device installed in the adjacent location, converts it into the Internet protocol, and sends the packet to the final destination server. Current LoRa Gateway uses a single-hop method, and each gateway must include a communication network capable of the Internet. If it is the mobile communication(i.e., WCDMA, LTE, etc.) network, it is required to pay the internet usage fee which is installed in each gateway. If the LoRa communication is frequent, the user has to spend a lot of money. We propose an idea on how to design a multi-hop protocol which enables packet routing between gateways by analyzing the LoRaWAN communication method implemented in its existing single-hop way in this paper. For this purpose, this paper provides an analysis of the standard specification of LoRaWAN and explains what was considered when such protocol was designed. In this paper, two gateways have been placed based on the functional role so as to make the multi-hop protocol realized: (i) hopping gateway which receives packets from the end-device and forwards them to another gateway; and (ii) main gateway which finally transmits packets forwarded from the hopping gateway to the server via internet. Moreover, taking into account that LoRaWAN is wireless mobile communication, a level-based routing method is also included. If the protocol proposed by this paper is applied to the LoRaWAN network, the monthly internet fee incurred for the gateway will be reduced and the reliability of data transmission will be increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.409-417
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• 2021

The standardization of weapon system parts is one of the elements of parts management and is an important factor for reducing the cost of acquiring and maintaining a weapon system, enhancing its reliability, improving interoperability, alleviating parts obsolescence problems, improving logistics efficiency, and strengthening the military's combat readiness. This study examined how to manage parts of domestic R&D weapon systems, overseas imports weapon system parts, and various commercial parts from a standardization perspective, and to study parts management methods for standardizing parts in the future. This system was used to achieve systematic part standardization in a military weapon system. To this end, this study investigated what elements are used to standardize weapon system parts. The importance and weight of each element were calculated using the AHP (Analytic Hierarchy Process), one of the decision-making techniques, and the design stage standards using the part selection method were studied. Through this, the selection process of standard parts, which has been made according to the experience and subjective judgment of designers and personnel, was improved to propose a systematic and objective method of standardizing weapons parts.

• Animal Bioscience
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• v.34 no.2
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• pp.163-171
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• 2021

Objective: Considering the importance of dairy farming and the negative effects of heat stress, more tolerant genotypes need to be identified. The objective of this study was to investigate the effect of heat stress via temperature-humidity index (THI) and diurnal temperature variation (DTV) in the genetic evaluations for daily milk yield of Holstein dairy cattle, using random regression models. Methods: The data comprised 94,549 test-day records of 11,294 first parity Holstein cows from Brazil, collected from 1997 to 2013, and bioclimatic data (THI and DTV) from 18 weather stations. Least square linear regression models were used to determine the THI and DTV thresholds for milk yield losses caused by heat stress. In addition to the standard model (SM, without bioclimatic variables), THI and DTV were combined in various ways and tested for different days, totaling 41 models. Results: The THI and DTV thresholds for milk yield losses was THI = 74 (-0.106 kg/d/THI) and DTV = 13 (-0.045 kg/d/DTV). The model that included THI and DTV as fixed effects, considering the two-day average, presented better fit (-2logL, Akaike information criterion, and Bayesian information criterion). The estimated breeding values (EBVs) and the reliabilities of the EBVs improved when using this model. Conclusion: Sires are re-ranking when heat stress indicators are included in the model. Genetic evaluation using the mean of two days of THI and DTV as fixed effect, improved EBVs and EBVs reliability.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.717-723
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• 2020

Determination of local tie vectors between the space geodetic techniques such as VLBI (Very Long Baseline Interferometer), SLR (Satellite Laser Ranging), DORIS (Doppler Orbit determination and Radiopositioning Integrated on Satellite), GNSS (Global Navigation Satellite System) is essential for combination of ITRF (International Terrestrial Reference Frame). Therefore, it is required to compute IVP (Invariant Point) position of each space geodetic technique with high accuracy. In this study, we have computed Sejong VLBI IVP position by using updated mathematical model for adjustment computation so that the improvement on efficiency and reliability in computation are obtained. The measurements used for this study are the coordinates of reflective targets on the VLBI antenna and their accuracies are set to 1.5 mm for each component. The results show that the position of VLBI IVP together with its standard deviation is successfully estimated when they are compared with those of the results from previous study. However, it is notable that additional terrestrial surveying should be performed so that realistic measurement errors are incorporated in the adjustment computation process.