• Earthquakes and Structures
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• v.18 no.3
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• pp.367-377
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• 2020

Incremental dynamic analysis (IDA) widely uses for the collapse risk assessment procedures of buildings. In this study, an IDA-based collapse risk assessment methodology is proposed, which employs a novel approach for detecting the near-collapse (NC) limit state. The proposed approach uses the modal pushover analysis results to calculate the maximum inter-story drift ratio of the structure. This value, which is used as the upper-bound limit in the IDA process, depends on the structural characteristics and global seismic responses of the structure. In this paper, steel midrise intermediate moment resisting frames (IMRFs) have selected as case studies, and their collapse risk parameters are evaluated by the suggested methodology. The composite action of a concrete floor slab and steel beams, and the interaction between the infill walls and the frames could change the collapse mechanism of the structure. In this study, the influences of the metal deck floor and autoclaved aerated concrete (AAC) masonry infill walls with uniform distribution are investigated on the seismic collapse risk of the IMRFs using the proposed methodology. The results demonstrate that the suggested modified IDA method can accurately discover the near-collapse limit state. Also, this method leads to much fewer steps and lower calculation costs rather than the current IDA method. Moreover, the results show that the concrete slab and the AAC infill walls can change the collapse parameters of the structure and should be considered in the analytical modeling and the collapse assessment process of the steel mid-rise intermediate moment resisting frames.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.347-351
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• 2020

A material changes its physical and chemical properties through the interaction with radiation and also the neutrons, which is electronically neutral so that the penetration depth is relatively deeper than that of other radioactive way including alpha or beta ray. Therefore, the radiation damage by neutron irradiation has been intensively investigated for a long time with respect to the safety of nuclear power plants. The damage induced by neutron irradiation begins with the creation of point defects in atomic scale in the unit of picoseconds, and their progress pattern can be characterized by microstructural defects, such as dislocation loops and voids. Their morphological characteristics affect the properties of neutron-irradiated materials, therefore, it is very important to predict the microstructure at a given neutron irradiation condition. This paper briefly reviews the evolution of radiation damage induced by neutron irradiation and introduces a phase-field model that can be widely used in predicting the microstructure evolution of irradiated materials.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.3
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• pp.23-30
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• 2002

In recently, using of steel reinforcements by reinforcing materials of the reinforced earth, micro-pile and root-pile etc,. is wide-spreading in the stabilizing control of cutting and embankment slopes, but the failure mechanism of reinforced earth as well as the effect of insert angles or types of reinforcement and others are not defined clearly. In this study, therefore heavy-duty direct shear tests were exercised on the reinforced soil and the non-reinforced soil, which was executed for research on the interaction of soil-reinforcement and theirs behavior. The hardness and softness and the standard sands were used for modeling of reinforced soil, the material constants for the computer simulation were estimated from the results of CD-Test. The effects of reinforcing and of friction increasing on the softness, area ratio of reinforcements is equal, were the better than them of the hardness, as well the reinforcing effects of shear strength without regard to the area ratio is much the same at $10^{\circ}$, insert angle of reinforced bar, differ from them of the existing study. Then, the results of numerical analysis showed that the behavior of reinforcements displayed bending resistance and shear resistance at $15^{\circ}$ and $30^{\circ}$, respectively. Also, the state of strain transfer was observed and the behavior of resistance mechanism on reinforcements presented almost the same them of landslides stabilizing pile.

• The Korean Journal of Applied Statistics
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• v.26 no.4
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• pp.623-634
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• 2013

In this study, we provide empirical evidence of whether a spatial correlation among mode choices at the TAZ(Traffic Analysis Zone) level exists based on transit smart card data observed in Seoul, Korea. The results show that the areas with a higher probability that passengers choose to take a bus are clustered and that those regions have fewer metro stations than bus stations. We also found that the spatial correlation turned out to be statistically meaningful and provided an opportunity for the potential use of the spatial correlation in modeling mode choices. A reliable spatial interaction would constitute valuable information for transportation agencies in terms of their route planning and scheduling based on the transit smart card data.

• Korean Journal of Health Education and Promotion
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• v.27 no.4
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• pp.165-175
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• 2010

Objectives: The purpose of this study is to evaluate the program theory of a lifestyle intervention program for the prevention and treatment of metabolic syndrome. Methods: The program evaluated is a tailored intervention for multiple health behavior associated with metabolic syndrome which is informed by theoretical constructs from the Intervention Mapping and Transtheoretical model. The program components include one-to-one health counseling, a self-management handbook, and a health diary. To evaluate program impact theory we examined the logic of program goals and objectives, intervention methods and strategies, and the theoretical constructs of program materials through document review and matrix building. Results: This evaluation has found that the intervention program applied social cognitive theory constructs to design intervention methods and strategies in addition to the Transtheoretical model: self-monitoring for goal setting and monitoring skill, outcome expectation for the benefits of health behavior change, and interaction with environment for observational learning through modeling. While the intervention addresses multiple determinants and behaviors, it is limited to an individual level and lacks social and environmental approaches. Following the Transtheoretical framework, the contents of the intervention materials were developed utilizing consciousness raising as a main strategy for earlier stages of change, and counterconditioning and stimulus control for later stages of change. Conclusion: Program theory evaluation can be a process of enhancing program validity. It would also be necessary for providing basis for efficient program implementation. When comparisons of program theory between similar programs are possible, program theory and validity will be strengthened when comparisons of program theories between similar programs are possible.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.115-118
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• 2011

Process characterization of the chemical mechanical polishing (CMP) process for undensified phosphosilicate glass (PSG) film is reported using design of experiments (DOE). DOE has been addressed to experimenters to understand the relationship between input variables and responses of interest in a simple and efficient way. It is typically beneficial for determining the adequate size of experiments with multiple process variables and making statistical inferences for the responses of interests. Equipment controllable parameters to operate the machine include the down force (DF) of the wafer carrier, pressure on the backside of the wafer, table and spindle speed (SS), slurry flow rate, and pad condition. None of them is independent; thus, the interaction between parameters also needs to be indicated to improve process characterization in CMP. In this paper, we have selected the five controllable equipment parameters, such as DF, back pressure (BP), table speed (TS), SS, and slurry flow (SF), most process engineers recommend to characterize the CMP process with respect to material removal rate (RR) and film uniformity as a percentage. The polished material is undensified PSG. PSG is widely used for the plananization in multi-layered metal interconnects. We identify the main effect of DF, BP, and TS on both RR and film uniformity, as expected, by the statistical modeling and analysis on the metrology data acquired from a series of $2^{5-1}$ fractional factorial design with two center points. This revealed the film uniformity of the polished PSG film contains two and three-way interactions. Therefore, one can easily infer that the process control based on better understanding of the process is the key to success in semiconductor manufacturing, typically when the wafer size reaches 300 mm and is continuously scheduled to expand up to 450 mm in or little after 2012.

• Structural Engineering and Mechanics
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• v.72 no.6
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• pp.689-712
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• 2019

Time-series models like AR-ARX and ARMAX, provide a robust way to capture the dynamic properties of structures, and their residuals can be effectively used as features for damage detection. Even though several research papers discuss the implementation of AR-ARX and ARMAX models for damage diagnosis, they are basically been exploited so far for detecting the time instant of damage and also the spatial location of the damage. However, the inverse problem associated with damage quantification i.e. extent of damage using time series models is not been reported in the literature. In this paper, an approach to detect the extent of damage by combining the ARMAX model by formulating the inverse problem as a multi-constrained optimization problem and solving using a newly developed hybrid adaptive differential search with dynamic interaction is presented. The proposed variant of the differential search technique employs small multiple populations which perform the search independently and exchange the information with the dynamic neighborhood. The adaptive features and local search ability features are built into the algorithm in order to improve the convergence characteristics and also the overall performance of the technique. The multi-constrained optimization formulations of the inverse problem, associated with damage quantification using time series models, attempted here for the first time, can considerably improve the robustness of the search process. Numerical simulation studies have been carried out by considering three numerical examples to demonstrate the effectiveness of the proposed technique in robustly identifying the extent of the damage. Issues related to modeling errors and also measurement noise are also addressed in this paper.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.1-8
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• 2002

In this paper, we propose a novel branch method which improve learning effects of the digital contents using a user-friendly access method by taking any conceptual object as the unit of interface. The conceptual objects may exist as a part of one or more contents pages, and we can access them to repeat, replay or return to the original branch point, that elevates the interactions of the digital contents. This method is useful for all kinds of digital contents, but it is especially effective to make educational contents in the field of science, engineering, and language courses because they contain various conceptual elements such as blocks of modeling, mathematical equations, and memorizing units. In addition, if we realize the blanch method proposed in this paper with the conventional page-branch or title-branch methods in the same contents, user interaction will be maximized and learning effects of the contents maybe beautifully improved.

• The Journal of the Korea Contents Association
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• v.13 no.2
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• pp.235-243
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• 2013

This study analyzes the interaction of variables consisting of the local finance system based on the theory of system thinking regarding how financial decentralization can be understood as the political means for local decentralization and why it is needed. The results gained from this research are as follows: first, variables consisting of the local finance system form interactional relationship in the significant level, and it has been found that rapid growth and rapid decline repeat with five positive feedback loops as the center. Second, strategic points for the validity of local finance decentralization were discovered through causal map modeling. In particular, it has been shown that the virtuous cycle structure declines the local finance system through the constant operation of variables (government subsidies, taxation for real estate transactions, central government's local finance mediation system, and local government debt, etc.) that deteriorate the vicious cycle structure. Based on this, strategic policy tasks were drawn. It is expected that this study will help the understanding of the local finance system and increase academic width for local finance from the aspects of general knowledge, not the knowledge about local finance decentralization.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.471-477
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• 2018

The purpose of this study is to develop an mobile augmented reality for students to learn bar placing work, which is increasingly utilized in the construction field. In order to improve the understanding of the structural drawing, a structural drawing is used as a marker image, and an augmented reality is realized by superimposing a virtual 3D bar placing model that is placed according to the structural drawing on the screen. In addition to the 3D modeling, the contents are developed so as to help students to learn the interpretation method of 2D drawings, the development and splices of reinforcing steel, bar fabricating practice according to KCI structural concrete design code, and the process of bar placing. The results show that the augmented reality is positively evaluated in terms of interface style, perceived usefulness, perceived ease of use, perceived enjoyment, attitude toward using, and intention to use. The augmented reality is worth to be introduced because it has advantages of visualization and interaction in terms of education.