• Smart Structures and Systems
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• v.24 no.2
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• pp.157-171
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• 2019

This study investigated the effects of the geometric parameters of superelastic shape memory alloy (SE SMA) fibers on the pullout displacement recovering and self-healing capacity of reinforced cementitious composites. Three diameters of 0.5, 0.7 and 1.0 mm and two different crimped lengths of 5.0 and 10.0 mm were considered. To provide best anchoring action and high bond between fiber and cement mortar, the fibers were crimped at the end to create spear-head shape. The single fiber cement-based specimens were manufactured with the cement mortar of a compressive strength of 84 MPa with the square shape at the top and a dog-bone shape at the bottom. The embedded length of each fiber was 15 mm. The pullout test was performed with displacement control to obtain monotonic or hysteretic behaviors. The results showed that pullout displacements were recovered after fibers slipped and stuck in the specimen. The specimens with fiber of larger diameter showed better displacement recovering capacity. The flag-shaped behavior was observed for all specimens, and those with fiber of 1.0 mm diameter showed the clearest one. It was observed that the length of fiber anchorage did not have a significant effect on the displacement recovery, pullout resistance and self-healing capacity.

• Earthquakes and Structures
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• v.16 no.6
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• pp.727-741
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• 2019

A reinforced concrete water tank is a typical functional liquid storage structure and cracks are the greatest threat to the liquid storage structure. Tanks are readily cracked due to seismic activity, thereby leading to the leakage of the stored liquid and a loss of function. In order to study the effect of cracks on liquid storage tanks, self-healing and leakage tests for bending cracks and through cracks in the walls of a reinforced concrete water tank were conducted. Material performance tests were also performed. The self-healing performance of bending cracks in a lentic environment and through cracks in a lotic environment were tested, thereby the self-healing width of bending micro-cracks in the lentic environment in the short term were determined. The through cracks had the capacity for self-healing in the lotic environment was found. The leakage characteristics of the bending cracks and through cracks were tested with the actual water head on the crack. The effects on liquid leakage of the width of bending cracks, the depth of the compression zone, and the acting head were determined. The relationships between the leakage rate and time with the height of the water head were analyzed. Based on the tests, the relationships between the crack characteristics and self-healing as well as the leakage were obtained. Thereby the references for water tank structure design and grading earthquake damage were provided.

• Geomechanics and Engineering
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• v.15 no.1
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• pp.615-620
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• 2018

In order to analyze the healing effectiveness of rock salt cracks affected by the applied stresses and time, we used the ultrasonic technology to monitor the ultrasonic pulse velocity (UPV) variations for different initial stress-damaged rock salts during self-healing experiments. The self-healing experiments were to create different conditions to improve the microcracks closure or recrystallized, which the self-healing effect of damaged salt specimens were analyzed during the recovery period about 30 days. We found that: The ultrasonic pulse velocity of the damaged rock salts increases rapidly during the first 9 days recovery, and the values gradually increase to reach constant values after 30 days. The damaged value and the healed value were identified based on the variation of the wave velocity. The damaged values of the specimens that are subject to higher initial damage stress are still keeping in large after 30 days recovery under the same recovery condition It is interesting that the damage and the healing were not in the linear relationship, and there also existed a damage threshold for salt cracks healing ability. When the damage degree is less than the threshold, the self-healing ratio of rock salt is increased with the increase in damage degree. However, while the damage degree exceeds the threshold, the self-healing ratio is decreased with the increase in damage.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1540-1546
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• 2014

In order to resolve coverage hole problems caused by indoor-BS (IBS) faults, we propose a new frame structure and practical algorithm based on optimization technique. Our main contributions can be described as follows: 1) a frame structure with healing channels for solving abnormal IBS faults; and 2) an efficient heuristic resource allocation algorithm with fixed IBS selection to reduce the complexity for the optimization problem. Through intensive simulations, we evaluate the performance excellency of our proposed algorithm with respect to average cell capacity and user fairness compared with conventional algorithms.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.167-168
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• 2006

Mobile Ad Hoc Networks (MANETs) has the characteristics such as dynamic network topology, constrained power capacity, constrained wireless bandwidth and quality, etc. For MANETs AODV (Ad-Hoc On-Demand Distance Vector) routing protocol has been proposed. However AODV routing protocol has some inefficiency related to re-routing path establishment corresponding to node's failure. In this paper, we propose a Self-Healing Routing Technique for MANETs that uses the one-hop nodes from the failed node to set up the routing path efficiently. We also include simulation results to show the performance of our method.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.437-444
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• 2015

In this age of digital technology, we often experience overwhelming and inescapable feelings of weakness, vulnerability, loneliness and fear that propel us into a state of gloom or frustration. Poetry can also serve as a therapeutic medium for overcoming them because it provides unique opportunities for self-discovery and is a catalyst for healing and self-integration. This study examines the healing properties in English poetry. First, Poetry has expressed innermost feelings, which can serve as a catharsis the emotional release. Therefore it can nurture and strengthen the human capacity. Poetic language heals our soul and mind. Rhythm which comes in many forms and poetic form also are important components of the therapeutic value of poetry. So we can say English poetry can be used as a therapeutic means for healing and personal growth.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.222-227
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• 2018

Recently, due to the deterioration and various natural disasters caused by the passage of concrete pole for 20~30 years or more, damage and destruction of the poles have increased the demand for maintenance. In this paper, 10 flexural strength test specimens were fabricated by using crack self - healing concrete of Fly ash, GGBS, CA, etc. The compressive strength of the concrete with slag was found to be excellent, but the concrete with fly ash was slightly below the reference strength. In addition, the crack loadings of the specimens satisfied the criteria of KS F 4304. In the case of the load-deflection and strain relations, the behavior of the fly ash specimens was similar, but in the specimens containing the blast furnace slag, The results showed that a large amount of strain occurred.

• Journal of the Korean Electrochemical Society
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• v.25 no.2
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• pp.51-68
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• 2022

Although lithium metal batteries have a high energy density, experimental skills capable of solving lots of problems induced by dendrite such as short circuit, low coulomb efficiency, capacity loss, and cycle performance are still only in academic research stage. In this paper, research cases for dendrite growth inhibition on lithium metal electrode were classified into four types: flexible SEI (solid electrolyte interface) layer responding to volume expansion of lithium metal electrode, SEI supporting layer to inhibit dendrite growth physically, SHES (self-healing electrostatic shield) mechanism to adjust lithium growth by leading uniform diffusion of Li⁺ ions, and finally micro-patterning to induce uniform deposition of lithium. We hope to advance the practical use of lithium metal electrode by analyzing pros and cons of this classification.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.387-395
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• 2022

PDRN (Polydeoxyribonucleotide) is a DNA-derived polymer that promotes self-renewal of damaged cells and tissues as a tissue regeneration active material. PDRN is a DNA fragment cut into small sizes by various physical or chemical methods. When administered to the body, PDRN binds and stimulates the adenosine A2A receptor on the surface of tissue cells to promote cell regeneration, accelerate wound healing, and reduce pain. Although PDRN is prepared from testis or semen of fish in most cass, PDRN extraction from various plants species was performed in the present study. Among 7 tested plant species, the highest DNA yield and purity was obtained form mugwort (Chrysanthemum coronarium, C.c), followed by broccoli (Brassica oleracea, B.o). Then, we evaluated the in vitro wound healing capacity of PDRNs prepared from these two selected plants. PDRN from C.c and B.o. significantly stimulated the wound healing process at ㎍/ml range. The present study suggests that PDRN from plant species can be an effective alternative to PDRN from marine organism.

• Journal of Korean Institute of Industrial Engineers
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• v.22 no.2
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• pp.303-311
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• 1996

The Self Healing Ring (SHR) is one of the most Intriguing schemes which provide survivability for telecommunication networks. To design a cost effective SONET ring it is necessary to consider load balancing problems by which the link capacity is determined. The load balancing problem in SONET ring when demand splitting is not allowed is considered in this paper. An efficient algorithm is presented which provides the best solution starting from various Initial solutions. The initial solution is obtained by routing ell demands such that no demands pass through an are In the ring. The proposed algorithm iteratively improves the Initial solution by examining each demand and selecting the maximum load are in its path. The demand whose maximum arc load is biggest is selected to be routed in opposite direction. Computational results show that the proposed algorithm is excellent both in the solution quality and in the computational time requirement. The average error bound of the algorithm is 0.11% of the optimum and compared to dual-ascent approach which has good computational results than other heuristics.