• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.60-63
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• 2023

The AlGaN/GaN heterostructure has high electron mobility due to the two-dimensional electron gas (2-DEG) layer, and has the characteristic of high breakdown voltage at high temperature due to its wide bandgap, making it a promising candidate for high-power and high-frequency electronic devices. Despite these advantages, there are factors that affect the reliability of various device properties such as current collapse. To address this issue, this paper used metal-organic chemical vapor deposition to continuously deposit AlGaN/GaN heterostructure and SiN passivation layer. Material and electrical properties of GaN HEMTs with/without SiN cap layer were analyzed, and based on the results, low-frequency noise characteristics of GaN HEMTs were measured to analyze the conduction mechanism model and the cause of defects within the channel.

• Journal of Practical Agriculture & Fisheries Research
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• v.8 no.1
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• pp.73-96
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• 2006

Today, producers of ginseng spray prohibited fertilizers or use excessive amount of fertilizers whereas distributers either claim that they are selling domestic ginseng when in fact they are selling imported ginseng, cheat on the age or weight of ginseng, or mix domestic and imported ginseng. In terms of quality in comparison with foreign ginseng, 90% of the people surveyed responded that domestic ginseng is more efficacious. When asked whether they would purchase foreign ginseng products when they become available in the market, only one of the respondents responded that he or she would purchase foreign ginseng whereas 50 respondents or 81% of the total surveyed responded that they wouldn't purchase foreign ginseng. About half of the respondents answered that when Chinese red ginseng, ginseng, or wild ginseng products cultivated with harmful fertilizers become available in the market, they would either reconsider purchasing ginseng products or stop purchasing ginseng products all together. In order to develop the ginseng industry 20 respondents (25%) chose the establishment of the standards, 33 respondents (42%) chose marking the place of origin, 15 respondents (19%) quality improvement, 7 respondents (9%) research on the efficacy, and 4 respondents (5%) said improvement on the storage methods as the important factors of the ginseng industry. Considering the fact that 77% of the respondents selected either the standardization or marking of the place of origin, the consumers seem to be demanding reliability in the distribution of ginseng products. Therefore, those people who work in the industry such as the producers, distributors and others should have a sense of mission to develop ginseng, which is a gift from God, and do their best to produce and distribute ginseng products.

• Proceedings of the ESK Conference
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• 1997.04a
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• pp.56-60
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• 1997

The study of human erroneous actions has traditionally taken place along two different lines of approach. One has been concerned with finding and explaining the causes of erroneous actions, such as studies in the psychology of "error". The other has been concerned with the qualitative and quantitative prediction of possible erroneous actions, exemplified by the field of human reliability analysis (HRA). Another distinction is also that the former approach has been dominated by an academic point of view, hence emphasising theories, models, and experiments, while the latter has been of a more pragmatic nature, hence putting greater emphasis on data and methods. We have been developing a method to make predictions about error modes. The input to the method is a detailed task description of a set of scenarios for an experiment. This description is then analysed to characterise thd nature of the individual task steps, as well as the conditions under which they must be carried out. The task steps are expressed in terms of a predefined set of cognitive activity types. Following that each task step is examined in terms of a systematic classification of possible error modes and the likely error modes are identified. This effectively constitutes a qualitative analysis of the possibilities for erroneous action in a given task. In order to evaluate the accuracy of the predictions, the data from a large scale experiment were analysed. The experiment used the full-scale nuclear power plant simulator in the Halden Man-Machine Systems Laboratory (HAMMLAB) and used six crews of systematic performance observations by experts using a pre-defined task description, as well as audio and video recordings. The purpose of the analysis was to determine how well the predictions matiched the actually observed performance failures. The results indicated a very acceptable rate of accuracy. The emphasis in this experiment has been to develop a practical method for qualitative performance prediction, i.e., a method that did not require too many resources or specialised human factors knowledge. If such methods are to become practical tools, it is important that they are valid, reliable, and robust.

• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.110-117
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• 2023

Reconstructing underwater geometry in real time with forward-looking sonar is critical for applications such as localization, mapping, and path planning. Geometrical data must be repeatedly calculated and overwritten in real time because the reliability of the acoustic data is affected by various factors. Moreover, scattering of signal data during the coordinate conversion process may lead to geometrical errors, which lowers the accuracy of the information obtained by the sensor system. In this study, we propose a three-step data processing method with low computational cost for real-time operation. First, the number of data points to be interpolated is determined with respect to the distance between each point and the size of the data grid in a Cartesian coordinate system. Then, the data are processed with a nonlinear interpolation so that they exhibit linear properties in the coordinate system. Finally, the data are transformed based on variations in the position and orientation of the sonar over time. The results of an evaluation of our proposed approach in a simulation show that the nonlinear interpolation operation constructed a continuous underwater geometry dataset with low geometrical error.

• Journal of Korean Society of Rural Planning
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• v.28 no.4
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• pp.83-91
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• 2022

The goal of this study is to promote the spread of environmentally friendly agricultural products, which have been receiving a lot of attention lately, as a way to improve food safety and quality. As a result of the increased labor input, increased production costs, and an aging population, environmentally friendly agriculture is making it more difficult for farmers to expand their enterprises. In the meantime, consumers find it difficult to spread eco-friendly agricultural products due to their high expectations for safety and quality, as well as the desire to purchase products at a reasonable price. Previous studies have revealed differences in perceptions between eco-friendly agricultural producers and consumers. In light of this, this study divided consumers based on their characteristics (such as age, purchase history, health concerns, etc.), and different policies were proposed in order to increase purchasing factors for each group based on their characteristics. In order to gather information for this study, general citizens were asked about their perceptions of eco-friendly agricultural products, future purchase intentions and awareness, reliability, necessity, purpose, and information sources. A two-step clustering analysis was conducted using nominal and continuous variables simultaneously. The paper presents the three derived group differences (senior organic interest group, middle-aged organic interest group, and indifferent young organics) as well as group differences for the purchasing/non-purchasing factor analysis and policy improvement for each group. An eco-friendly agricultural product distribution proposal was made at the end of this article.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.67-76
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• 2007

Raining method has been widely used for preparing sand specimen because of its ability to reconstitute the homogeneous specimen with desired relative density and its reliability established by the numerous experiments on diverse influential factors. In conventional raining methods, adjustment of relative density is achieved by controlling the shutter porosity and the whole system is required to be re-adjusted to achieve the target relative density when the granular characteristics are changed. It is also observed from conventional methods that certain degrees of spatial variation in density exist and the limited range of relative density is reproduced. In this paper, raining system with porous plate is proposed. It is shown that the wide range of relative density can be achieved by controlling failing height only. This enhanced system is able to obviate the subtle control of shutter porosity and minimize the effect of falling distance, which in turn ensures the homogeneity of the specimen, especially for low relative density.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.369-378
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• 2022

This study analyzed the effect of aesthetic elements of characters on viewing immersion and re-watching intentions in Chinese historical dramas. For the empirical study, frequency analysis, factor analysis, reliability analysis, correlation analysis, and regression analysis were performed using SPSS 23.0 based on the questionnaire of 330 Chinese who watched the historical drama . As a result of the study, it was found that the character aesthetic elements of Chinese historical dramas with hair and costumes had a positive effect on viewing immersion and re-watching intentions. In addition, it was found that viewing immersion had a mediating effect on the relationship between aesthetic factors and re-viewing intention. It is expected that continuous character creation can be expected through various aesthetic elements such as hair and clothes to increase the value of dramas in the future.

• Physical Therapy Korea
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• v.30 no.3
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• pp.194-201
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• 2023

Background: Falls are a common and serious problem in the elderly population. Muscle strength and balance are important factors in the prevention of falls. The Y-balance test (YBT) is used to assess dynamic postural control and shows excellent test-retest reliability. However, no studies have examined the relationship between lower-limb strength and YBT scores in elderly women. Objects: This study aimed to examine the relationship between lower-limb strength and YBT scores in elderly women. Methods: Thirty community-dwelling elderly women participated in the study. Lower-limb strength including hip flexor, hip extensor, hip abductor (HAB), hip adductor (HAD), knee flexor, knee extensor, ankle dorsiflexor, and ankle plantar flexor (PF) muscles was examined using a smart KEMA strength sensor (KOREATECH Inc.), and the YBT was used to assess dynamic balance. Relationship between lower-limb strength and YBT was demonstrated using a Pearson's correlation coefficient. Results: HAB strength (r = 0.388, p < 0.05), HAD strength (r = 0.362, p < 0.05), and ankle PF strength (r = 0.391, p < 0.05) positively correlated with the YBT-anterior direction distance. Ankle PF strength was positively correlated with the YBT-posteromedial direction distance (r = 0.396, p < 0.05) and composite score (r = 0.376, p < 0.05). Conclusion: The results of this study suggest that HAB, HAD, and ankle PF strengths should be considered for dynamic postural control in elderly women.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.2D
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• pp.183-190
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• 2009

In order to improve continuous success and stabilization of high-speed rail in the future, Using Frequency of high-speed rail should be enhanced by improving satisfaction of high-speed rail passenger. High-speed rail is needed to hold the priority in competition means by comparing the traits of service of domestic air lines. This study utilizes structural equation modeling to develop model for estimating factors influencing to service through conducting survey questionnaire. It also uses reliability analysis, correlation analysis, factor analysis to examine the rationalization of items and to establish hypothesis of this research. The results show that KTX contains 'inner service' item that is considered to be ameliorated and that domestic airline present low performance of 'outer service' item. In other words, moving section which partly is under a limited condition is needed to be improved. In addition, access to airport and transfer to other transportations have to be improved as they show the lowest satisfaction.

• The Korean Journal of Franchise Management
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• v.7 no.1
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• pp.21-29
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• 2016

Purpose - The primary purpose of this study is to employ effective marketing methods using market segmentation of coffee shops by determining how motivations to visit coffee shops have different impacts on demographic profile of visitors and characteristics of coffee shop visits, so as to draw out a better understanding of customers of coffee market. Research design, data, and methodology - Data were collected using surveys of self-administered questionnaires toward coffee shop users in Daejeon, Korea. A number of samples used in data analysis were 253 excluding unusable responses. The data were analyzed through frequency, reliability, and factor analysis using SPSS 20.0. Factor analysis was conducted through the principal component analysis and varimax rotation method to derive factors of one or more eigen values. In addition, the cluster analysis, multivariate ANOVA, and cross-tab analysis were used for the market segmentation based on the types of motivation for coffee shop visits. The process of the cluster analysis is as follows. Four clusters were derived through hierarchical clustering, and k-means cluster analysis was then carried out using mean value of the four clusters as the initial seed value. Result - The factor analysis delineated four dimensions of motivation to visit coffee shops: ostentation motivation, hedonic motivation, esthetic motivation, utility motivation. The cluster analysis yielded four clusters: utility and esthetic seekers, hedonic seekers, utility seekers, ostentation seekers. In order to further specify the profile of four clusters, each cluster was cross tabulated with socio-demographics and characteristics of coffee shop visits. Four clusters are significantly different from each other by four types of motivations for coffee shop visits. Conclusions - This study has empirically examined the difference in demographic profile of visitors and characteristics of coffee shop visits by motivation to visit coffee shops. There are significant differences according to age, education background, marital status, occupation and monthly income. In addition, coffee shops use pattern characterization in frequency of visits to coffee shops, relationships with companion, purpose of visit, information sources, brand type, average expense per visit, important elements of selection attribute were significantly different depending on motivations for coffee shop visits.