• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.88-96
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• 2020

In this study, the effect of cyclic wetting-drying on the self-healing of cementitious materials containing superabsorbent polymers (SAPs) were experimentally evaluated. In each cycle, cracked cement paste specimens containing various SAP dosages were exposed to wet conditions for 1 h, during which the capillary water absorption tests and water flow tests were conducted, and then exposed to dry conditions for 47 h. The capillary water absorption test results showed that the sorptivity values of the specimen without SAPs, SAP 0.5%, SAP 1.0%, and SAP 1.5% specimens were decreased by approximately 22.9%, 36.8%, 42.8%, and 46.3%, respectively, after 8 cycles. In addition, the water flow test results showed that the amount of water runoff through the cracks of all cracked specimens gradually decreased over wet/dry cycles, especially the reduction ratio of the amount of water runoff increased with increasing SAP dosage. Furthermore, the swelling behavior of SAPs in cracks by in gress water was con firmed via X-ray computed tomography (CT) analysis. These results indicate that the effective crack width can be reduced as SAPs absorb water and swell, while the water absorbed in SAPs can be released to crack surfaces under dry conditions, further promoting healing product formation. This study demon strates that the in corporation of SAPs can in crease the water tightness of cracks, thereby improving the self-healing efficiency of cementitious materials.

• Composites Research
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• v.16 no.2
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• pp.54-61
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• 2003

In this study, manufacturing process for microcapsules with the self-healing agent was introduced and the characteristics of microcapsules manufactured by varying with various manufacturing process variables were evaluated through a particle size analyzer, an optical microscope, and a TGA. Urea-formaldehyde resin was used for the thin wall of microcapsules and DCPD (dicyclopentadiene) was used for the self-healing agent. The various manufacturing process variables, such as (1) 24hr, 40hr, 48hr, 60hr of the solution time of the EMA copolymer, (2) pH3.5, pH4.0, pH4.5 of the hydrogen ion concentration of the emulsified solution, (3) 400rpm, 500rpm, 600rpm, 1000rpm of the agitation speed of the emulsified solution, (4) $50^{\circ}$, $55^{\circ}$, $60^{\circ}$ of the reaction temperature of the emulsified solution, were considered. According to the results, the particle size distribution of microcapsules was affected on the agitation speed, and the thermal stability of microcapsules was influenced by the solution time of the EMA copolymer, the hydrogen ion concentration, and the reaction temperature of the emulsified solution. Therefore, suitable manufacturing process variables should be applied to obtain thermally stable microcapsules capable of containing the healing agent capable until the thin wall of microcapsules were to be burned.

• Journal of Digital Convergence
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• v.19 no.3
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• pp.273-278
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• 2021

The purpose of this study is to help self-healing by identifying self-description by utilizing the self-description diagnosis of literary therapy and the resonance of the work narrative. Therefore, the research was conducted through the methodology of literature therapy, which uses the self-introduction team of literary therapy and basic photography team to understand their own narrative and to heal themselves through resonance with the work narrative. Through this study, we understood that it is possible to understand and identify and understand one's psychological problems through self-description and self-culture techniques. This case study revealed that it can be used as a new technique for understanding self-description by applying the methodology of literary therapy and for healing self-exploration through resonance with the work narrative.

• Korean Institute of Interior Design Journal
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• v.26 no.6
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• pp.13-23
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• 2017

The purpose of this study is to analyze the expression method according to the planning of townhouse and the healing method that affects residents for communicating with natural environment, in order to propose resident-focused communication with nature for healing. The results are as follows. First, the expression of nature elements can be divided into 'direct' and 'indirect' and healing effects through nature can be divided into 'body' and 'psychology'. The healing method of residents through nature was classified into physical and psychological healing through openness, familiarity, comfort, and stability. Second, as an expression method according to townhouse planning, the arrangement plan induced active communication with nature through the arrangement according to topography and a common garden. In terms of construction plan, a bigger window or door than that of other residential spaces was installed on a wall, ceiling or opening to directly bring the nature of outside visually for more communication. Third, with regard to healing methods of townhouse, 'openness' which reduces depression and increases self-esteem, expands the view of residents. 'Familiarity', the healing method that can relieve the fatigue of eyes and bring psychological warmth and comfort, makes us feel familiar through the pattern and texture of woods and stones that are natural materials. 'Comfort' which heals residents by creating an outside space and bringing the nature elements through a huge window can provide psychological healing such as eased tension in daily life as well as physical healing such as vitamin D synthesis and the recovery of physiological function. Also, 'Stability' gives a comfortable feeling by applying the colors of finishing materials inside or seeing the colors of surrounding nature as it is through big windows. Finally, in order to support the results of this study more objectively, a follow-up study conducting a survey on the residents of townhouse is needed.

• Clean Technology
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• v.17 no.2
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• pp.85-96
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• 2011

Self-healing materials are a class of smart materials that have the structurally incorporated ability to repair damage caused by mechanical usage over time. A material (polymers, ceramics, metals, etc.) that can intrinsically correct damage caused by normal usage could lower production costs of a number of different industrial processes through longer part lifetime, reduction of inefficiency over time caused by degradation, as well as prevent costs incurred by material failure. The recent announcement from Nissan on the commercial release of scratch healing paints for use on car bodies has gained public interest on such a wonderful property of materials. This article is a second part of healing materials dealing with inorganic engineering materials such as metals, ceramics, and concrete. The healing mechanisms developed for the inorganic materials are to be discussed with the future prospect.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.2
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• pp.119-130
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• 2007

Home service networked systems require a high-availability service with a proactive and practical fault management. However, as the system complexity grows, it is not easy to meet the requirement. Moreover, user may want to pay no attention to a sequence of complex or nervous maintenance jobs for system fault managements. Therefore, the home service networked systems must have self & remote fault management capability with a minimal human intervention for meeting high-availability requirement of the integrated systems that consist of the networked appliances or devices. In this paper, we present an autonomic healing utility equipped with a remote self-managing mechanism in order to both increase the availability of home service networked systems and decrease the maintenance cost.

• Smart Structures and Systems
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• v.17 no.1
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• pp.135-147
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• 2016

This paper describes a smart structural system, which uses smart materials for real-time monitoring and active control of bolted-joints in steel structures. The goal of this research is to reduce the possibility of failure and the cost of maintenance of steel structures such as bridges, electricity pylons, steel lattice towers and so on. The concept of the smart structural system combines impedance based health monitoring techniques with a shape memory alloy (SMA) washer to restore the tension of the loosened bolt. The impedance-based structural health monitoring (SHM) techniques were used to detect loosened bolts in bolted-joints. By comparing electrical impedance signatures measured from a potentially damage structure with baseline data obtained from the pristine structure, the bolt loosening damage could be detected. An outlier analysis, using generalized extreme value (GEV) distribution, providing optimal decision boundaries, has been carried out for more systematic damage detection. Once the loosening damage was detected in the bolted joint, the external heater, which was bonded to the SMA washer, actuated the washer. Then, the heated SMA washer expanded axially and adjusted the bolt tension to restore the lost torque. Additionally, temperature variation due to the heater was compensated by applying the effective frequency shift (EFS) algorithm to improve the performance of the diagnostic results. An experimental study was conducted by integrating the piezoelectric material based structural health monitoring and the SMA-based active control function on a bolted joint, after which the performance of the smart 'self-monitoring and self-healing bolted joint system' was demonstrated.

• CELLMED
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• v.13 no.10
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• pp.9.1-9.6
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• 2023

This study aims to explore the potential of Korean language learning as a means of psychological healing and improving the quality of life for Japanese middle-aged and older learners. Results showed that Korean language learning could help alleviate various psychological issues experienced by middle-aged learners and contribute to enhancing their quality of life. Learning a foreign language is not just about acquiring information but also about meeting people who use the language and understanding and experiencing their culture. In particular, for Japanese middle-aged learners, Korean language learning can be advantageous as it can lead to the discovery or development of new hobbies or interests. Results also showed that Korean language learning increased learners' opportunities for interaction with others and enjoyment of learning new cultural customs. These positive outcomes suggest the need for discussion of teaching strategies that focus on psychological healing in foreign language education. Further clinical trials with participants who learn foreign languages for healing purposes may provide more conclusive evidence on the diverse effects of language learning on stress, anxiety, depression, self-development, social connections, and cognitive ability.

• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.310-318
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• 2006

In this study, we investigate the feasibility of in-situ crack propagation by using a double cleavage drilled compression (DCDC) specimen showing a slow crack velocity down to 0.03 mm/s under 0.01 mm/s of displacement control. Finite element analysis predicted that the DCDC specimens would show at least 4.3 fold delayed crack initiation time than conventional tensile fracture specimens under a constant loading speed. Using DCDC specimens, we were able to observe the in-situ crack propagation process in a particle reinforced transparent polymer composite. Our results confirmed that the DCDC specimen would be a good candidate for the in-situ observation of the behavior of particle reinforced composites with slow crack velocity, such as the self-healing process of micro-particle reinforced composites.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.81-84
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• 2001

A signal path control switch has been designed and implemented with AT&T 0.5${\mu}{\textrm}{m}$ CMOS ORCA FPGA. This device controls the path of digital signals in SDH-based transmission system. The proposed switch is suitable for self-healing operation which protects against transmission network failure. The self-healing operation of the switch is effectively done by the reconfigurable information stored in the registers of the switch. This device consists of eight subparts such west-east transmitting parts, west-east receiving parts, add-drop control parts, AIS control Part, and CPU interface part. The device is capable to a ring network as well as a linear network.