• Earthquakes and Structures
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• v.18 no.3
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• pp.391-405
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• 2020

The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.

• Journal of Internet Technology
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• v.19 no.6
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• pp.1801-1810
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• 2018

In this study, an energy-aware data-replication is proposed to effectively support a mobile sink in a solar-powered wireless sensor network (WSN). By utilizing the redundant energy efficiently, the proposed scheme shares the gathered data among the cluster heads using a backbone network, in order to increase data-reliability. It also maintains a backup cluster head in each cluster to enhance topological resilience. The simulation result showed that, compared to conventional clustering techniques, the proposed scheme decreases the total amount of data loss from the mobile sink as well as saving its energy (by reducing its moving distance), while minimizing the unexpected blackout time of the sensor node.

• Journal of the Korea Society for Simulation
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• v.16 no.4
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• pp.57-65
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• 2007

In many sensor network applications, sensor nodes are deployed in open environments, and hence are vulnerable to physical attacks, potentially compromising the node's cryptographic keys. False sensing report can be injected through compromised nodes, which can lead to not only false alarms but also the depletion of limited energy resource in battery powered networks. Fan Ye et al. proposed that statistical en-route filtering scheme(SEF) can do verify the false report during the forwarding process. In this scheme, the choice of a partition value represents a trade off between resilience and energy where the partition value is the total number of partitions which global key pool is divided. If every partition are compromised by an adversary, SEF disables the filtering capability. Also, when an adversary has compromised a very small portion of keys in every partition, the remaining uncompromised keys which take a large portion of the total cannot be used to filter false reports. We propose a fuzzy-based adaptive partitioning method in which a global key pool is adaptively divided into multiple partitions by a fuzzy rule-based system. The fuzzy logic determines a partition value by considering the number of compromised partitions, the energy and density of all nodes. The fuzzy based partition value can conserve energy, while it provides sufficient resilience.

• Korean Journal of Artificial Intelligence
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• v.11 no.2
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• pp.1-6
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• 2023

This paper presents a comprehensive scheme for assessing the importance of multiple microgrids (MGs) network that includes distributed energy resources (DERs), renewable energy systems (RESs), and energy storage system (ESS) facilities. Due to the uncertainty of severe weather, large-scale cascading failures are inevitable in energy networks. making the assessment of the structural vulnerability of the energy network an attractive research theme. This attention has led to the identification of the importance of measuring energy nodes. In multiple MG networks, the energy nodes are regarded as one MG. This paper presents a modified PageRank algorithm to assess the importance of MGs that include multiple DERs and ESS. With the importance rank order list of the multiple MG networks, the core MG (or node) of power production and consumption can be identified. Identifying such an MG is useful in preventing cascading failures by distributing the concentration on the core node, while increasing the effective link connection of the energy flow and energy trade. This scheme can be applied to identify the most profitable MG in the energy trade market so that the deployment operation of the MG connection can be decided to increase the effectiveness of energy usages. By identifying the important MG nodes in the network, it can help improve the resilience and robustness of the power grid system against large-scale cascading failures and other unexpected events. The proposed algorithm can point out which MG node is important in the MGs power grid network and thus, it could prevent the cascading failure by distributing the important MG node's role to other MG nodes.

• Steel and Composite Structures
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• v.22 no.3
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• pp.589-611
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• 2016

The primary objectives of this research are to investigate the energy factor response of steel moment resisting frame (MRF) systems equipped with fuses subject to ground motions and to develop an energy-based evaluation approach for evaluating the damage-control behavior of the system. First, the energy factor of steel MRF systems with fuses below the resilience threshold is derived utilizing the energy balance equation considering bilinear oscillators with significant post-yielding stiffness ratio, and the effect of structural nonlinearity on the energy factor is investigated by conducting a parametric study covering a wide range of parameters. A practical transformation approach is also proposed to associate the energy factor of steel MRF systems with fuses with classic design spectra based on elasto-plastic systems. Then, the energy balance is extended to structural systems, and an energy-based procedure for damage-control evaluation is proposed and a damage-control index is also derived. The approach is then applied to two types of steel MRF systems with fuses to explore the applicability for quantifying the damage-control behavior. The rationality of the proposed approach and the accuracy for identifying the damage-control behavior are demonstrated by nonlinear static analyses and incremental dynamic analyses utilizing prototype structures.

• Steel and Composite Structures
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• v.32 no.2
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• pp.265-279
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• 2019

The self-centering capacity and energy dissipation performance have been recognized critically for increasing the seismic performance of structures. This paper presents an innovative steel moment frame with self-centering steel reinforced concrete (SRC) wall panel incorporating replaceable energy dissipation devices (SF-SCWD). The self-centering mechanism and energy dissipation mechanism of the structure were validated by cyclic tests. The earthquake resilience of wall panel has the ability to limit structural damage and residual drift, while the energy dissipation devices located at wall toes are used to dissipate energy and reduce the seismic response. The oriented post-tensioned strands provide additional overturning force resistance and help to reduce residual drift. The main parameters were studied by numerical analysis to understand the complex structural behavior of this new system, such as initial stress of post-tensioning strands, yield strength of damper plates and height-width ratio of the wall panel. The static push-over analysis was conducted to investigate the failure process of the SF-SCWD. Moreover, nonlinear time history analysis of the 6-story frame was carried out, which confirmed the availability of the proposed structures in permanent drift mitigation.

• Environmental and Resource Economics Review
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• v.25 no.2
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• pp.179-197
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• 2016

The development of overseas resource is a driving force to secure the energy security in Korea with low sufficiency rate of energy. This paper analyzes the effect of overseas oil resource development on the economy by presenting a real business cycle model with consolidated energy price index. A linear-quadratic dynamic programming is adopted to raise computational transparency and efficiency. The analysis shows that the overseas oil resource development project during 2010 and 2012 decreases the energy price by 1.2% per annum which effect is equivalent to the positive 0.47% to the GDP. The implication calls for steady and robust support for overseas resource development projects to enhance energy resilience.

• Fashion & Textile Research Journal
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• v.16 no.5
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• pp.791-799
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• 2014

For development of dyeability, the rayon fabrics were dyed repeatedly with persimmon juice by padding mangle. The merit of padding-based dyeing was easier color reproduction over traditional hand dyeing where various colors and color fastness to light and laundering are hard to obtain. We evaluated the mechanical properties and hand value by Kawabata Evaluation system for dyed rayon fabrics. The results obtained from this study were as follows. With the increase of repeating padding times of dyeing, the linearity load-extension curve and tensile energy per unit length of the rayon fabrics were increased, but the tensile resilience of fabrics were decreased. The value of shear stiffness and shear hysteresis were increased. Also compression resilience and linearity of compression thickness were increased. The rayon fabrics dyed with persimmon juice had shown the thickness and weight increase as the number of padding increase. As repeating times of dyeing with persimmon juice were increased, among the 6 hand values, the item of koshi(stiffness) and Hari(anti-drape stiffness), fukurami(fullness and softness) were increased. while Shinayakasa (flexibility with soft feeling) and Shari(crispness) were greately decreased. The amount of coated persimmon juice on the surface of the fabric was gradually increased as the padding times of dyeing.

• The korean journal of orthodontics
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• v.43 no.1
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• pp.29-34
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• 2013

Objective: To examine the prophylactic potential of 3 orthodontic bonding adhesives: Fuji Ortho SC, Illuminate, and Resilience. Methods: Thirty-six Wistar Wag rats were randomly divided into 4 groups consisting of 9 rats each. One of the groups received no treatment and was used as a control. In the other groups, individual bands coated with one of the 3 adhesives were cemented to the lower incisors. Enamel samples were obtained after 6 and 12 weeks and analyzed using scanning electron microscopy in combination with energy dispersive spectrometry. Results: Six weeks after band cementation, no fluoride was found in the enamel of the lower incisors. After 12 weeks, there was no fluoride in the enamel of teeth coated with the Resilience composite. However, in the case of the Illuminate composite and the resin-modified glass ionomer Fuji Ortho SC cement, the depth of fluoride penetration reached $2{\mu}m$ and $4.8-5.7{\mu}m$, respectively. Conclusions: Fluoride ions from orthodontic adhesives can be incorporated into the surface layer of the enamel. Orthodontists may apply orthodontic adhesives, such as the Fuji Ortho SC, to reduce the occurrence of caries during orthodontic treatment with fixed appliances.

• Textile Coloration and Finishing
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• v.24 no.4
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• pp.296-304
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• 2012

For development of dyeability, the cotton fabric was dyed repeatedly with persimmon juice by padding mangle. We evaluated the mechanical properties and hand value by Kawabata Evaluation System, and observed the change of surface morphology. The results obtained from this study were as follows. With the increase of repeating padding times of dyeing, the linearity of load-extension curve and tensile energy per unit length of the cotton fabric were increased, but the tensile resilience of fabric was decreased. The value of shear stiffness and shear hysteresis were increased. Also compression resilience and linearity of compression thickness curve were increased. The cotton fabric dyed with persimmon juice had shown the thickness and weight increase as the number of padding increase. As repeating times of dyeing with persimmon juice were increased, among the 6 hand values, the item of stiffness, anti-drape stiffness, fullness and softness were increased, while flexibility with soft feeling and crispness were greatly decreased. The amount of coated persimmon juice on the surface of the fabric was gradually increased as the padding times of dyeing. And cotton fabrics were dyed evenly with persimmon juice by padding mangle.