• Structural Engineering and Mechanics
• /
• v.55 no.3
• /
• pp.675-686
• /
• 2015

The use of ground granulated blast furnace slag (GGBFS) from steel industries waste is showing perspective application in civil engineering as partial substitute to cement. Use of such waste conserves natural resources and minimizes the space required for landfill. The GGBFS used in the present work is of ultra fine size and hence serves as micro filler. In this paper strength and durability characteristics of ultra fine slag based high strength concrete (HSC) (with a characteristic compressive strength of 50 MPa) were studied. Cement was replaced with ultra fine slag in different percentages of 5, 10, and 15% to study the compressive strength, porosity, resistances against sulfate attack, sorptivity and chloride ion penetration. The experiments to study compressive strength were conducted for different ages of concrete such as 7, 28, 56, and 90 days. From the detailed investigations with 16 mix combinations, 10% ultra fine slag give better results in terms of strength and durability characteristics.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2002.10a
• /
• pp.325-328
• /
• 2002

Recently, attempts to use indigenous plants have been made for the recovery of nature of slopes and making permanent vegetation group, harmonizing with surroundings from the ecological perspective. For surface failure prevention of slopes, indigenous plants are known as superior to those of exotic grasses, but studies how much indigenous plants influence shear strength of soil is lacking. Therefore, in this study, strength increasement of the root-soil system were investigated for four indigenous plants.

• Journal of the Korea Convergence Society
• /
• v.11 no.1
• /
• pp.337-347
• /
• 2020

The purpose of this study was to investigate the effects of strengths perspective group art therapy on the strength-related perspectives on the stress, depression and impulsivity of male middle school students who smoke. Data were collected from 15 middle school smokers from two middle schools in A city. Among them, 8 experimental groups and 7 other control groups were willing to participate in art therapy. The collected data were analyzed by nonparametric test considering the number of groups was 15. The Mann-Whitney U test and Wilcoxon signed ranks test were performed. As a result, the strength-focused group art therapy program showed stress (z = -2.521, p <.05), depression (z = -2.527, p <.05), impulse (z = -2.371, p < .05). Therefore, it can be found that strengths perspective group art therapy has a positive effect on the psychological well-being of smoking middle school students, and furthermore, it is necessary to study the deep emotional state of smoking middle school students.

• International Journal of Aeronautical and Space Sciences
• /
• v.16 no.4
• /
• pp.537-547
• /
• 2015

A Monte Carlo (MC) simulation was conducted to predict the reliability of a newly developed pyrotechnic pin puller. The reliability model is based on the stress-strength interference model that states that failure occurs if the stress exceeds the strength. In this study, the stress is considered to be the energy consumed by movement of a pin shaft, and the strength is considered to be the energy generated by pyrotechnic combustion for driving the pin shaft. Failure of the pin puller can thus be defined as the consumed energy being greater than the generated energy. These energies were calculated using a performance model formulated in the previous study of the present authors. The MC method was used to synthesize the probability densities of the two energies and evaluate the reliability of the pin puller. From a probabilistic perspective, the calculated reliability was compared to a deterministic safety factor. A sensitivity analysis was also conducted to determine which design parameters most affect the reliability.

• Journal of Contemporary Eastern Asia
• /
• v.20 no.2
• /
• pp.108-128
• /
• 2021

Research on the news coverage of North Korea has been paying less attention to social media platforms than to legacy media. An increasing number of social media users post, retweet, share, interpret, and set agendas on North Korea. The accessibility of international users and North Korea's publicity purposes make social media a venue for expression, news diversity, and framing about the nation. This study examined the sentiment of Twitter posts on North Korea from a framing perspective and the relationship between network strengths and sentiment from a social network perspective. Data were collected using two tools: Jupyter Notebook with Python 3.6 for preliminary analysis and NodeXL for main analysis. A total of 11,957 tweets, 10,000 of which were collected using Python and 1,957 tweets using NodeXL, about North Korea between June 20-21, 2020 were collected. Results demonstrated that there was more negative sentiment than positive sentiment about North Korea in the sampled Twitter posts. Some users belonging to small network sizes reached out to others on Twitter to build networks and spread positive information about North Korea. Influential users tended to be impartial to sentiment about North Korea, while some Twitter users with a small network exhibited high percentages of positive words about North Korea. Overall, marginalized populations with network bonding were more likely to express positive sentiment about North Korea than were influencers at the center of networks.

• Geomechanics and Engineering
• /
• v.24 no.5
• /
• pp.419-430
• /
• 2021

Investigation on the compressibility and shear strength of compacted loess is of great importance for the design and operation of engineering infrastructures in filling area. In this study, the mechanical behaviors of Yan'an compacted loess are investigated at various dry densities and water contents by conducting one dimensional compression and direct shear tests. And the elastic compressibility, plastic compressibility, yield stress and strength are obtained from the experiments. Results show that when water content increases, plastic compressibility parameter increases, but yield stress decreases. However, the increase of dry density leads to a decrease in plastic compressibility parameter but an increase in yield stress. In addition, elastic compressibility parameter is found to be a constant which is irrelevant to water content and dry density. As for strength, cohesion and internal friction angle is directly proportional to dry density, but inversely proportional to water content. Moreover, the mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) tests were also performed to observe the pore size distribution and microstructure of the specimens. Finally, by using results of MIP and SEM tests, the compressibility and strength behaviours of Yan'an compacted loess are explained from the perspective of pore-size distribution and microstructure.

• Culinary science and hospitality research
• /
• v.22 no.6
• /
• pp.33-51
• /
• 2016

The hotel industry needs to make the competitive advantage difficult to be imitated in order to remain sustainable in competitive business circumstances. Front-line employees' service-oriented citizenship behaviors(OCBs) can be such a strength from the perspective of organizational system. With an aim of investigating the antecedents of the hotel front-line employees' service-oriented OCBs, this study proposed a theoretical framework linking authentic leadership to service-oriented OCBs with goal commitment as a mediator. A total of 260 cases without missing values have been used for the final analysis and structural equation modeling (SEM) is employed using the SPSS and AMOS 7. It was first found that self-awareness and relational transparency of authentic leadership made a significant impact on their goal commitment while balanced processing and moral perspective failed to influence them. Second. goal commitment influenced all sub-factors of service-oriented OCBs. Third, moral perspective and relational transparency of authentic leadership significantly influenced service-oriented OCBs while self-awareness and relational transparency failed to make it. Finally, goal commitment significantly makes an intervening effect for the relationship between self-awareness & service-oriented OCBs and relational transparency & service-oriented OCBs but failed to intervene the other relationships. The results provide theoretical and practical implications regarding directions of leadership styles and HR management in the hotel industry and suggestions for the further extended studies.

• Computers and Concrete
• /
• v.19 no.6
• /
• pp.651-658
• /
• 2017

High-performance concrete, besides aggregate, cement, and water, incorporates supplementary cementitious materials, such as fly ash and blast furnace slag, and chemical admixture, such as superplasticizer. Hence, it is a highly complex material and modeling its behavior represents a difficult task. This paper presents an evolutionary system for the prediction of high performance concrete strength. The proposed framework blends a recently developed version of genetic programming with a local search method. The resulting system enables us to build a model that produces an accurate estimation of the considered parameter. Experimental results show the suitability of the proposed system for the prediction of concrete strength. The proposed method produces a lower error with respect to the state-of-the art technique. The paper provides two contributions: from the point of view of the high performance concrete strength prediction, a system able to outperform existing state-of-the-art techniques is defined; from the machine learning perspective, this case study shows that including a local searcher in the geometric semantic genetic programming system can speed up the convergence of the search process.

• The International Journal of Costume Culture
• /
• v.9 no.1
• /
• pp.77-81
• /
• 2006

From the viewpoint of color perspective, black has more obvious effects to impart images than dress itself This study aims to examine black dress through the fashion history to highlight the aesthetic value of black and to make better use of black in designing. Black in fashion, particularly in the guise of the little black dress, became an indispensable feature of cosmpolitan style after World War I. Designers harnessed the power of black, drawn irresistibly to its innate qualities of drama and strength of line. For the past five hundred years, aside from the use of black for mourning as well as for religious, academic, legal and ceremonial dress, black with a greater or lesser dominance has been a fashion constant. Since then black has been an important color in fashion. How to use black in formative designs should be studied continuously.

• Journal of the Korean Ceramic Society
• /
• v.40 no.7
• /
• pp.625-631
• /
• 2003

Recent work at USC has focused on strategies to enhance the toughness and overall mechanical performance of polymer foams for use in lightweight sandwich structures. Both mechanical and chemical approaches have been employed with reasonable success. Fiber reinforcement, though difficult from a processing perspective, can lead to substantial enhancements in toughness and strength, while reducing friability. Chemical modifications are also challenging from a processing perspective, but can produce similar enhancements in performance. Efforts to enhance performance of phenolic foam and PVC foam through fiber reinforcement and chemical modification are described, along with the resulting enhancements in performance.