• Journal of Welding and Joining
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• v.24 no.1
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• pp.43-49
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• 2006

This paper describes the friction surface modification which has been successfully developed with the friction stir welding recently There are several problems including just position control and backlash in conventional friction surface modification system. Therefore it has been developed the friction surface modification system which has been controlled precisely both position and force by driving hydraulic cylinder in this paper. The mechtrode rotation speed(N) and feeding speed(Vz), travel speed(Vx,y) are of critical importance for the width and thickness of the coating in friction surfacing process. But there is no theoretical method of determining interrelations between process parameters affect the coating width and thickness. As a result of DOE(design of experiment) with developed system, the coating thickness and width seemed to decrease according to increase the mechtrode rotation speed(N) and traveling speed(Vx,y), to decrease feeding speed(Vz) apparently. However as the result of regression analysis the main effect was only the mechtrode rotation speed in the coating thickness.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.241-248
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• 2019

In this paper, we aim to check the reliability growth of multiple launch rocket components by the life evaluation. We apply the Crow-AMSAA model to the sets of test data obtained from the development phase. The result of the data analysis shows that the reliability of some components needs to be improved. In order to improve their reliability, we analyze the failure mechanism and change their designs. The verification of the reliability growth for those components is done by analyzing the data sets obtained by the accelerated life tests. As a result, we show that the MTBF of those components is increased and also their reliabilities improved.

• Steel and Composite Structures
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• v.50 no.4
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• pp.443-458
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• 2024

The construction industry, one of the biggest producers of greenhouse emissions, is under a lot of pressure as a result of growing worries about how climate change may affect local communities. Geopolymer concrete (GPC) has emerged as a feasible choice for construction materials as a result of the environmental issues connected to the manufacture of cement. The findings of this study contribute to the development of machine learning methods for estimating the properties of eco-friendly concrete, which might be used in lieu of traditional concrete to reduce CO₂ emissions in the building industry. In the present work, the compressive strength (f_c) of GPC is calculated using random forests regression (RFR) methodology where natural zeolite (NZ) and silica fume (SF) replace ground granulated blast-furnace slag (GGBFS). From the literature, a thorough set of experimental experiments on GPC samples were compiled, totaling 254 data rows. The considered RFR integrated with artificial hummingbird optimization (AHA), black widow optimization algorithm (BWOA), and chimp optimization algorithm (ChOA), abbreviated as ARFR, BRFR, and CRFR. The outcomes obtained for RFR models demonstrated satisfactory performance across all evaluation metrics in the prediction procedure. For R² metric, the CRFR model gained 0.9988 and 0.9981 in the train and test data set higher than those for BRFR (0.9982 and 0.9969), followed by ARFR (0.9971 and 0.9956). Some other error and distribution metrics depicted a roughly 50% improvement for CRFR respect to ARFR.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.18 no.2
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• pp.67-79
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• 2023

The bounce rate is the rate at which a user leaves immediately after visiting, and this study aimed to find out what attributes of a website affect the bounce rate. Web site evaluation items were defined as a total of 4 items and 27 evaluation attributes, including usability, information, service interaction, and technology, so that they can be commonly applied to venture companies in various industries through prior research. As a result of the study, 6 website attributes that affect the bounce rate were verified to be significant by discriminant analysis and decision tree analysis. Suggestions to reduce the bounce rate of venture business websites through this study are as follows. First, the path name of the website is displayed as mandatory and a pull-down menu function is added to facilitate movement to other pages. Second, it is good to expose core content that can attract users' attention in the form of a banner, and place internal link banners in the right place on sub-pages. Third, external links should be linked to a new window so that they do not leave the current page immediately so that they can be re-entered. Lastly, it is recommended to expose the contact information of the person in charge and consultation function as direct information for communication with customers, but if individual response is difficult, at least the consultation function must be added. These suggestions are expected to be of practical help in various fields such as website development, operation, and marketing. However, in special cases, a high bounce rate may be normal, so it should be considered according to the situation.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.117-123
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• 2013

The purpose of this research is to suggest the reasonable method of Network RTK surveying in future cadastral re-survey project through the accuracy analysis about Network RTK surveying achievement and the conventional TS-based confirmation surveying. To achieve it, we selected the experiment places and succeeded in achieving the result by Network RTK surveying about total of 307 parcel boundary point. We compared it with the result of confirmation surveying for cadastral, and it was shown that total connection errors of RMSE was ${\pm}0.1028m$ and total 48 places exceeded in the cadastral re-survey allowable error tolerance. The research suggested the practical alternatives in cadastral re-survey project after the comprehensive evaluation of those analysis results. Therefore, the author suggested development and adoptation of integrated electronic plane table surveying method. Moreover, we suggested unifying the first parcel boundary point method into the total station surveying and adopt the Network RTK surveying on the cadastral surveying inspection.

• Fashion & Textile Research Journal
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• v.10 no.6
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• pp.926-935
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• 2008

The field of textile and fashion is regard to be sensitive to trend, however, the professional fashion information planning company for trend forecasting has not settled down in Korea. This study was designed to propose systemizing for fashion trend information planning in domestic fashion information service market. The empirical research was conducted by analysing in-depth interview data and news-scrap contents about each fashion information planning company. The result are as follows; First, fashion information service showed a little difference according to the type of fashion information companies, but they provided not only general fashion trends but also external market environmental information, survey-based consumer information and various segmented market research reports including academic information. Second, the fashion information planning process is largely divided into 3 stages; trend analysis, trend forecasting, trend application. The trend application step is the stage which connects the fashion information service industry to the fashion business. Thirdly, as a result of the competitive power evaluation for fashion information planning, the domestic fashion information planning companies came to reveal the fact that the possibility of carrying out and information analysis power were weak, however, how to present trend information had a relatively competitive. Consequently, this study is expected to play a role in understanding the importance of fashion trend information, and further ahead it would be helpful to organize the curriculum of fashion information planning subject in order to educate the future fashion executives.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.78-87
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• 2017

The goal of the present paper is to objectify the intrinsic subjectivity of sound as a media of music by applying psycho-acoustical methodology to the analysis of a musical work. First, 18 sound samples are extracted from "Symponie Fantastique" written by Hector Berlioz, which is a piece of program music, and then the objective Zwicher's sound quality parameters such as: Loudness, Sharpness, Roughness and Fluctuation Strength are evaluated for each of these sound samples. For subjective sound quality evaluation, 9 representative sound quality adjectives are extracted on a basis of program feature of Symponie Fantastique and the first jury test is carried out by using the numeric rating method and the paired comparison method. Three sound quality adjectives, "bright", "noisy", and "realistic" are extracted from the factor analysis of the first jury test result. On a basis of the computed sound metrics and the second jury test result for the three sound quality adjectives, three sound quality indexes are developed to represent the sound qualities of "Symponie Fantastique".

• The Journal of Korean Association of Computer Education
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• v.22 no.3
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• pp.25-35
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• 2019

The backward design suggested in the 2015 revised curriculum takes into consideration the consistency between a goal and its evaluation, and emphasizes the essence of knowledge. However, the method for designing lesson plans is different from those of the past and, as a result, teachers in the field have experienced some difficulty in applying the design. Accordingly, this study was aimed at examining the differences between the taxonomy of educational objectives with which teachers are familiar and the viewpoint of informatics. The result of the analysis indicated no difference when applying the hierarchy of the six-sided view of the concept of understanding, of which teachers felt some difficulty in terms of applying the backward design. However, the analysis did show some similarity to the hierarchy of the six levels suggested in the taxonomy of the educational objectives. In general, when a new theory is suggested, it is very difficult for it to be accepted and applied. This study holds significance in that it suggests that a new theory must be accepted on the basis of sufficient analysis along with the necessity of efforts to be dedicated in order to increase its applicability.

• Journal of Environmental Impact Assessment
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• v.6 no.2
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• pp.113-121
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• 1997

LHR(Landfill Hazard Ranking Model) was developed for assessing the relative hazard of landfills by using the method of value-structured approach. LHR consists of combining a multiattribute decision-making method with a qualitative risk assessment approach. A pairwise comparision method was applied to determine weights of landfill factors related. To prove the validity of weights allocation of landfill hazard evaluation factors, sensitivity analysis was applied. Firstly, the impact on landfill hazard score according to variations of weights of landfill hazard factors was analyzed. Secondly, the impact on landfill hazard score according to conditions change of landfill hazard factors was analyzed. As a result of sensitivity analysis, LHR composite scores are largely influenced by some factors following sequential order such as waste volume, proximity to sensitive environments, containment facilities, distance from drinking water supplies, and waste toxicity. The relative order of landfill hazard evaluated by LHR is not influenced by the weights change of individual factors. Therefore, LHR seems to be a credible model to determine priorities of landfill remediation based on the vulnerability of water resources.

• Land and Housing Review
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• v.2 no.1
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• pp.35-46
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• 2011

This paper aims at examining the indices and their weights for the evaluation of local government to allocate reconstruction charge and reviewing the availability of them simulating local governments' evaluation. There has been no specific evaluation criteria existed, while central government has to allocate the reconstruction charge to local governments by the provision 3 of Restitution of Housing Reconstruction Gains Act. The results as follows : According to a survey on evaluation indices weight and AHP analysis, the weight of 'the housing welfare improve effort' is the highest with 25.1% among 5 upper-classification indices. Following this, each weight of 'housing welfare conditions(22.7%)', 'housing SOC establishment(22.5%)', 'the achievement and planning on reconstruction charge use(15.8%)', and 'housing sector achievement such as Bogeumjari(13.9%)' are ranked. Meanwhile, Among 16 lower-classification indices, 'the rate of minimum housing standard households(11.5%)', 'public rental housing supply(8.9%)', 'reconstruction charge use achievement(8.3%)', 'reconstruction charge use planning submit(7.5%)', and 'rate of water and sewage(6.3%)' hold high rank. The analysis results show the weight of 'housing sector achievement such as Bogeumjari' on the existing provisions should be decreased(30%${\rightarrow}$13.9%) as others' weight has to be slightly increased. According to the result of the simulation, Jeonbuk, Gyeongbuk, Jeonnam, Jeju, Gyeonggi received higher scores in the comprehensive evaluation, while Daejeon, Seoul, Incheon, Daegu and Gwangju, where the housing conditions are relatively good, received lower scores. These results of the analysis correspond with the direction of reconstruction charges allocation and indicate that the evaluation criteria used in this simulation is acceptable.