• Journal of Environmental Science International
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• v.19 no.5
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• pp.639-646
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• 2010

Differently from fly ash, the bottom ash produced from incinerated urban solid waste has been treated as an industrial waste matter, and almost reclaimed a tract form the sea. If this waste material is applicable to foam concrete as an fine aggregate, however, it may be worthy of environmental preservation by recycling of waste material as well as reducing self-weight of high-rising structure and long-span bridge. This research has an objective of evaluating the effects of application of bottom ash on the mechanical properties of foam concrete. Thus, the ratio of bottom ash to cement was selected as a variable for experiment and the effect was tested by compression strength, flexural strength, absorption ratio, density, expansion factor. It can be observed from experiments that the application ratios have different effects on the material parameters considered in this experiment, thus major relationship between application ratio and each material parameter were finally introduced. The result of this study can be applied to decide a optimal mix design proportion of foam light-weight concrete while bottom ash is used as an fine aggregate of the concrete.

• Journal of IKEEE
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• v.24 no.4
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• pp.1034-1038
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• 2020

In order to effectively process target recognition using radar, accurate signal information for the target is required. However, such a target signal is usually mixed with noise, and this part of the study is continuously carried out. Especially, image processing, target signal processing and target recognition for the target are examples. Since the field of target recognition is important from a military point of view, this paper carried out research on target recognition of aircraft using a tree-structured fuzzy neural networks. Fuzzy neural networks are learned by using reflected signal data for an aircraft to optimize the model, and then test data for the target are used for the optimized model to perform an experiment on target recognition. The effectiveness of the proposed method is verified by the simulation results.

• Journal of Korea Trade
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• v.25 no.1
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• pp.133-151
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• 2021

Purpose - This study examines the effects of expatriate transfer on foreign affiliate's labor productivity. Design/methodology - Using Korean-owned foreign affiliate-level data, we estimate the effect of expatriate transfer on foreign affiliate's labor productivity using the system generalized method of moments model. We also consider foreign affiliate- and host country-specific contingencies and test how they are associated with expatriates in enhancing foreign affiliate's labor productivity. Findings - We consider foreign production intensity and cultural distance between the home (i.e., South Korea) and host countries as key contingencies that influence the effect of expatriates on foreign affiliate's labor productivity. We find that expatriates are effective in enhancing the labor productivity of less production-intensive foreign affiliates. This effect is strengthened as expatriates are deployed to countries that share cultural similarities with the home country. Originality/value - Considering that previous studies provide mixed results on the effect of expatriates, our findings suggest that foreign affiliate-specific operational orientation and cultural distance should be considered jointly to understand the true effect of expatriate staffing on foreign affiliate performance.

• Asia pacific journal of information systems
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• v.34 no.2
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• pp.421-446
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• 2024

Through Information and Communication Technology (ICT), the growth of music streaming platforms has revolutionized music consumption. "Digital Shadow Work" (DSW) refers to unpaid labor in digital spaces, with some prior research on its aspects. However, a comprehensive understanding is hindered by limitations in existing studies such as a lack of universality and dynamic exploration. To address these gaps and enable a comprehensive investigation into the role of DSW within highly versatile digital applications such as digital streaming platforms, this study employs a grounded theory methodology, a qualitative approach well-suited for exploring the intricacies of DSW among users of Chinese music streaming applications over a two-month period, involving longitudinal interviews with nine participants. The study findings elucidate the dynamic nature of DSW perceptions, which fluctuate across different stages of use and change in intensity over time. This study uncovers mixed attitudes towards DSW tasks, and observes a waning enthusiasm for social features over time, prompting some users to consider switching platforms. This study highlights the importance of thoughtful and user-centric feature development to enhance user satisfaction and the understanding of DSW, providing practical design and enhancement implications for music streaming applications.

• Journal of Korean Academy of Nursing
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• v.45 no.6
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• pp.939-948
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• 2015

Purpose: An emerging trend in Asian higher education is English-medium instruction (EMI), which uses English as the primary instructional language. EMI prepares domestic students for international leadership; however, students report difficulty in learning, and educators have raised questions concerning the effectiveness of EMI. The flipped learning model (FLM), in which lecture and homework activities for a course are reversed, was applied to an English-medium course offered by a college of nursing in Korea. The aims of this study were to: 1) revise an existing English-medium nursing course using the FLM; 2) explore students' learning experiences and their acceptance of the FLM; and 3) identify key factors in the success of FLM. Methods: We used a descriptive, cross-sectional, mixed-methods design and the participants were students at one nursing school in Korea. A series of course development meetings with faculties from the nursing school and the center for teaching and learning were used to develop the course format and content. We conducted course evaluations using the Flipped Course Evaluation Questionnaire with open-ended questions and focus group interviews. Results: Students (N=75) in a 15-week nursing course responded to a survey after completing the course. Among them, seven students participated in one of two focus groups. Overall, students accepted and favored the flipped learning strategy, and indicated that the method enhanced lecture content and their understanding of it. Factors associated with effective instruction included structured monitoring systems and motivational environments. Conclusion: The FLM requires sufficient preparation to facilitate student motivation and maximize learning outcomes.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1352-1358
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• 2009

As the demand for a convergence between construction technologies and IT is on the rise, as seen in the visualization of U-City construction, studies on the ways in which IT in should be utilized in the building and construction field have been continuously and actively performed. However, there has been almost no development of standardized technology criteria relating to the life cycle of a building (planning, design, construction, and maintenance). That is, there are almost no examples of efforts made to combine construction technology and IT in a fundamental way, considering the environment, the facility, its spatial characteristics, engineering, materials, and structure, aspects that are commonly required not only for interior spaces but also for exterior construction of U-City. Despite the fact that a state-of-the-art infrastructure has been built, and the competency of users with the cutting-edge technology, composite studies on technologies, facilities, services and spaces are still lacking, and basic research on the composite operation method including compatibility and linkage between facilities and services within a U-City has been insufficient as well. It is generally known that by fusing IT with construction technologies, the total period of construction taken can be reduced and construction expenses can be curtailed, while construction quality can be improved. For this reason, it is vital to prepare a standardized base to connect cutting-edge IT with the construction technologies. In preparing such a base, the most urgent issue is to develop standardized technology criteria. The ultimate objective of this research is to establish the technological criteria system required to apply construction-IT fused technologies to U-Cities, and to develop the technological criteria for the design, construction and maintenance of the U-Cities. This paper, whose objective is to establish development strategies for construction-IT fused technologies by way of analyzing the criteria for conventional construction projects, the necessity of criteria for construction-IT fused technologies, and the current status of U-Cities' development, is the underlying research for this purpose. The strategies established are expected to be utilized in establishing the system of criteria for construction-IT fused technologies, and to contribute to a knowledge base in the construction-IT field. In addition, based on the strategies established, criteria for construction-IT fused technologies, such as design criteria and construction standards, will be developed, and by applying these criteria and standards, the ultimate objectives of U-Cities, which are the enhancement of urban competitiveness and the satisfaction of residents, will be attained

• Fashion & Textile Research Journal
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• v.7 no.4
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• pp.387-393
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• 2005

This study compares shamans' costumes of Korea with those of Siberia and Central Asia. It also investigates the meaning of shamanism and shamans,the relationship of Korean shamanism to shamanism, and the genealogy of Korean shamanism. For collecting and analyzing data of the research, literature reviews, field studies, and the investigation of historical relics are mostly used. The following are the major findings of the research: Through the comparison of shamans' costumes of Korea with those of Siberia and Central Asia, this research finds out some similarities and differences in the costumes. Both Korean shamans and Siberian and Central Asian shamans wore shaman's costumes and used utensils like bells or mirrors when they perform a religious service. On their costumes, they both used an element which stands for birds. However, they were different in terms of the materials or styles of the costumes, of the function of the costumes, and of the decorating with ornaments. The differences in the materials or styles of the costumes, different functions of the costumes, and using ornaments or not can be viewed as a general phenomenon, which is resulted from different environments. The soul's departing the body or the possession or a mixed method can be considered as mere variations due to regional or cultural differences. In conclusion, based on the comparison of the costumes of shamans of Korea with those of Siberia and Central Asia, the shamans of Korea and Siberia and Central Asia share the same origin. And the genealogy of Korean shamans can be said to be originated from the northern shamanism.

• Journal of the Korean Geotechnical Society
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• v.24 no.10
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• pp.105-111
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• 2008

To improve the stability of levee structure, it is required to use good quality fill materials, intensive management, appropriate hydraulic structure and construction of cut-off wall. In particular, the most important factor of levee construction technology is to use bed sediment for its safety. In this study, seepage model test and numerical analysis were performed based on a standard section of levee recommended in the river design standard of korea (2005). The results of test and analysis show that most of the bed soil is a sand (SP in USCS), which does not satisfy the permeability criteria for levee materials ($< k=10^{-3}cm/sec$), thus for the safety of levee it is required to adopt a stabilizing method such as good quality soil mixing, water content control.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.87-95
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• 2018

PURPOSES : A geo-grid pavement, e.g., a stress-absorbing membrane interlayer (SAMI), can be applied to an asphalt-overlay method on the existing surface-pavement layer for pavement maintenance related to reflection cracking. Reflection cracking can occur when a crack in the existing surface layer influences the overlay pavement. It can reduce the pavement life cycle and adversely affect traffic safety. Moreover, a failed overlay can reduce the economic value. In this regard, the objective of this study is to evaluate the bonding properties between the rigid pavement and a SAMI by using the direct shear test and the pull-off test. The predicted fractural energy functions with the shear stress were determined from a numerical analysis of the moving average method and the polynomial regression method. METHODS : In this research, the shear and pull-off tests were performed to evaluate the properties of mixtures constructed using no interlayer, a tack-coat, and SAMI with fabric and without fabric. The lower mixture parts (describing the existing pavement) were mixed using the 25-40-8 joint cement-concrete standard. The overlay layer was constructed especially using polymer-modified stone mastic asphalt (SMA) pavement. It was composed of an SMA aggregate gradation and applied as the modified agent. The sixth polynomial regression equation and the general moving average method were utilized to estimate the interlayer shear strength. These numerical analysis methods were also used to determine the predictive models for estimating the fracture energy. RESULTS : From the direct shear test and the pull-off test results, the mixture bonded using the tack-coat (applied as the interlayer between the overlay layer and the jointed cement concrete) had the strongest shear resistance and bonding strength. In contrast, the SAMI pavement without fiber has a strong need for fractural energy at failure. CONCLUSIONS : The effects of site-reflection cracking can be determined using the same tests on cored specimens. Further, an empirical-mechanical finite-element method (FEM) must be done to understand the appropriate SAMI application. In this regard, the FEM application analy pavement-design analysis using thesis and bonding property tests using cored specimens from public roads will be conducted in further research.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.2
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• pp.153-160
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• 2020

In this study, the optimum ratio of soil-cement was derived to utilize carbon capture minerals(CCM) as soil-cement for deep mixing method, quality characteristics of soil-cement mixed with carbon capture minerals were evaluated. The CCM is generated in the form of a slurry, and as a result of evaluating water content, it was found to be about 50%. Accordingly, the water content of CCM was removed in the unit water of Soil-cement mix. As a result of field mixing of soil-cement using CCM on field soil, it showed that the design allowable bearing capacity was satisfied by showing 3.0MPa or more as of 28 days of age. As a result of the hazard verification of carbon capture minerals, 0.055mg/L of Cu was detected, but satisfies the acceptance criteria, and no other harmful substances were eluted.