• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.150-156
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• 2017

This study examined the stress recovery length due to the local damage of a 7-wire strand, which is applied widely to PSC (Post Tensioned Concrete) bridges and cable-stayed bridges. The 7-wire strand is a multiple stranded steel of PC prestressing strand. Owing to the nature of the material, it is damaged continuously after completion with corrosion being the main cause of damage. On the other hand, due to its structural characteristics, it is difficult to grasp the degree of damage inside the cable and the pattern of stress variation. In the case of cables applied to bridges, the parts that are susceptible to corrosion are generated depending on the water supply and installation shape, which may cause local damage. This study analyzed the tendency of performance degradation and stress recovery length according to local damage of a 7-wire strand, which is applied mainly to bridge post-tensioning or stay cables. This study developed a computer-based simulation model that was validated with experimental results. The model developed in this study can be used to evaluate the safety level and estimate the remaining life span of P SC bridges or cable-stayed bridges.

• Clinical and Experimental Pediatrics
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• v.50 no.3
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• pp.272-276
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• 2007

Purpose : Bell's palsy is defined as an idiopathic facial nerve paralysis of sudden onset. In spite of intensive clinical and experimental investigation, there is still uncertainty in the incidence, etiology, and preferred mode of treatment in children. The objective of this study was to analyze clinical outcome and prognosis of children with Bell' palsy. Methods : We analyzed 61 cases of Bell's palsy diagnosed at the Department of Wonkwang University Hospital from January 1998 to July 2006. The inclusion criteria were any children with acute isolated unilateral lower motor neuron type of facial nerve palsy. The clinical findings and investigations were reviewed including age, sex, affected site, seasonal incidence and result of steroid treatment. Chi-square and Fisher's exact test was used to compare clinical outcome between duration of complete recovery and age. Results : There was no difference in incidence according to sex or age. Incidence was higher in summer and winter. There was no difference in complete recovery rate and duration between steroid treated group and control group. In the group of children younger than 6 years, duration of complete recovery was shorter than older children. Conclusion : We found increasing the incidence of Bell's palsy in summer and winter. Children younger than 6 years had shorter duration in complete recovery.

• Journal of Life Science
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• v.32 no.7
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• pp.567-577
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• 2022

Recently, the prevalence of ischemic diseases, such as ischemic heart disease, cerebral ischemia, and peripheral arterial disease, has been continuously increasing due to the aging population. The current standardized treatment for ischemic diseases is reperfusion therapy through pharmacotherapy and surgical approaches. Although reperfusion therapy may restore the function of damaged arteries, it is not effective at restoring the function of the surrounding tissues that have been damaged due to ischemia. Therefore, it is necessary to develop a new treatment strategy that can safely and effectively treat ischemic damage and restore the function of surrounding tissues. To overcome these limitations, stem cell-based therapy to regenerate the damaged region has been studied as a promising strategy for ischemic vascular diseases. Mesenchymal stem cells (MSCs) can be isolated from diverse tissues and have been shown to be promising for the treatment of ischemic disease by regenerating damaged tissues through immunomodulation, the promotion of angiogenesis, and the secretion of various relevant factors. Moreover, new approaches to enhancing MSC function, such as cell priming or enhancing transplantation efficiency using a 3D culture method, have been studied to increase stem cell therapeutic efficacy. In this review, we provide various strategies by which MSCs are used to treat ischemic diseases, and we discuss the challenges of MSC transplantation, such as the differentiation, proliferation, and engraftment of MSCs at the ischemic site.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.112-122
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• 2023

To restore the ecological function of contaminated soil and maximize the ecological services provided by the soil, besides the toxicity orrisk caused by pollutants, the functional aspects of the soil ecosystem should be considered. In this study, a method for evaluating the health of cleaned soil was presented, and the applicability of the proposed evaluation method was examined by applying it to soil treated with washing and landfarming. Productivity, habitat, water retention capacity, nutrient cycling, carbon retention capacity, and buffering capacity were used as soil health evaluation indicators. The results showed that the soil health was not completely recovered after remediation, and even in the case of the washed soil, the health was lower than before remediation. On the other hand, there was no significant change in soil quality due to oil pollution, but soil health deteriorated. Unlike the slightly improved soil quality after landfarming treatment, soil health was not completely restored. Therefore, the results of this study indicate that it is desirable to consider both soil quality and health when evaluating the remediation effect. The soil health evaluation method proposed in this study can be usefully utilized for the sustainable use of cleaned soil and to promote ecosystem services.

• Journal of Life Science
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• v.33 no.5
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• pp.436-444
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• 2023

Scientific training, diet, and ergogenic aids are widely used to overcome the limits of humans' physical abilities and to achieve excellent sports records. The adoption of nutritional strategies is important for athletes to perform at their highest level, and one of the main factors determining endurance ability is increased fat metabolism. A ketogenic diet (high fat, low carbohydrates) has thus been proposed as an alternative strategy to maximize fatty acid oxidation during prolonged periods of exercise. However, studies have shown mixed results regarding the ergogenic value of a ketogenic diet. For this reason, exogenous ketone supplements (EKS, ingestible forms of ketone bodies, ketone esters, and/or salts) have been suggested to obtain nutritional ketosis, an acute transient increase in circulating acetoacetate (AcAc) and b-hydroxybutyrate (bHB) concentrations, without limiting carbohydrate intake. Some studies have suggested the beneficial effects of EKS on the performance of endurance exercises by providing an additional fuel substrate for peripheral tissues, such as cardiac and skeletal muscles, sparing carbohydrates/increasing fat oxidation and post-exercise recovery by increasing glycogen resynthesis in the liver/muscle, attenuating protein degradation, stimulating protein synthesis in the skeletal muscle, etc. However, many studies have failed to observe the beneficial effects of EKS as an ergogenic aid. As such, this review summarizes the theoretical basis of, as well as the proposed and proven effects of EKS on exercise performance and recovery to date.

• Conservation Science in Museum
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• v.15
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• pp.38-55
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• 2014

Three costumes excavated from the tomb of Yu Gyeongjong ^1565-1623, which are now own at Buyeo National Museum, underwent conservation treatment. As a result of this treatment, the costume types were correctly identified and their original forms were restored. Through the restoration process, various key features were discovered, enabling the costume types to be correctly identified as a dallyeong ^{Official's Uniform with Round Collar}, jingnyeong ^{Coat with Straight Collar}, and changui ^{Coat with Slits in the Rear and Sides}. One of the newly discovered key features was a new variety of pattern that differed from the prevalent cloud pattern of the time. Also, on the dallyeong, it was found that the ground of the hyungbae ^{Rank Badge}, was made from yeongeumsa ^{Wrapped Gold Thread}. These costumes are significant artifacts showing trends, patterns, forms, and other key characteristics of clothing from the late sixteenth to the early seventeenth century.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.9 no.1
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• pp.59-69
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• 2001

The rotor blade is modeled using a composite box beam with arbitrary wall. The active constrained damping layers are bonded to the upper and lower surfaces of the box beam to provide active and passive damping. A finite element model, based on a hybrid displacement theory, is used in the structural analysis. The theory is capable of accurately capturing the transverse shear effects in the composite primary structure, the viscoelastic and the piezoelectric layers within the ACLs. A reduced order model is derived based on the Hankel singular value. A linear quadratic Gaussian (LQG) controller is designed based on the reduced order model and the available measurement output. However, the LQG control system fails to stabilize the perturbed system although it shows good control performance at the nominal operating condition. To improve the robust stability of LQG controller, the loop transfer recovery (LTR) method is applied. Numerical results show that the proposed controller significantly improves rotor aeromechanical stability and suppresses rotor response over large variations in rotating speed by increasing lead-lag modal damping in the coupled rotor-body system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1372-1382
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• 1999

The major source of errors in high-speed networks such as Broadband ISDN(B-lSDN) is buffer overflow during congested conditions. These congestion errors are the dominant sources of errors in 1high-speed networks and result in cell losses. Conventional communication protocols use error detection and retransmission to deal with lost packets and transmission errors. However, these conventional ARQ(Automatic Repeat Request) methods are not suitable for the high-speed networks since the transmission delay due to retransmissions becomes significantly large. As an alternative, we have presented a method to recover consecutive cell losses using forward error correction(FEC) in ATM(Asynchronous Transfer Mode)networks to reduce the problem. The performance estimation based on the cell discard process model has showed our method can reduce the cell loss rate substantially. Also, the performance estimations in ATM networks by interleaving and IP multicast service are discussed.

• Membrane Journal
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• v.9 no.3
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• pp.185-192
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• 1999

The ultrafiltration characteristics of wafer processing wastewater produced from semicon¬ductor industry was investigated for wastewater reuse. Using the pilot-scale ultrafiltration system con¬taining poly sulfone hollow fiber membranes (MWCO : 10,000, 20,000, 30,(00), the membrane performance, such as flux, rejection rate and concentration factor for flux was examined. The SDhs, turbidity, electrical conductivity and concentration of Si particles were measured, and the possibility of permeate reuse was validated from the experimental results. It was shown that the flux was recovered by the sweeping with air and water effectively. The permeate flux of 30,000 MWCO membrane was about 5 times higher than that of 10,000 and 20,000 MWCO membranes. The concentration of Si particle in the saw wastewater was analyzed 3.8-5.6 mg/$\ell$ and that of Si particle in the permeate was analyzed less than 0.2${\mu}g$/$\ell$. This means the rejection of silicon particle was over 96%.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.451-457
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• 2016

Prosthodontic decision-making process is done through analysis of clinical information and mutual communication between patient and dentist. When opposing teeth are extruded due to missing tooth or tooth defects, selection of appropriate treatment plan and predictory prognosis can be complicated in functional rehabilitation. In case of severely disharmonious occlusal plane result from extruded teeth, re-establishment of the occlusal plane is required, if necessary via prudent evaluation. In this case, class III patient had unesthetic appearance and mastication discomfort caused by disharmonious occlusal plane due to severe extrusion. Through a structured diagnostic process, appropriate treatment plan was selected. Esthetic and functional results were obtained through from full mouth rehabilitation with re-establishment of the occlusal plane.