• 한국가스학회지
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• 제12권2호
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• pp.53-56
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• 2008

용접 부위의 결함을 비파괴적으로 탐지하기 위하여 홀센서에 의해 누설자속을 측정할 수 있는 시스템과 4 종류의 용접결함을 갖는 기준시편을 제작하였다. 제작한 시스템으로 시편에 생성시킨 4 종류의 결함에서 누설된 자속을 측정하였고, 신호의 피크-피크 크기와 피크-피크 간의 간격에서 결함의 종류를 구분할 수 있는 가능성을 확인하였다.

• Journal of Acupuncture Research
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• 제36권4호
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• pp.251-255
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• 2019

Background: Low-level laser therapy (LLLT) including laser acupuncture (LA) has been widely used to treat chronic low back pain (CLBP), but there is no critically appraised evidence of the potential benefits. The purpose of this protocol for a systematic review was to enable the evaluation of the effectiveness of LLLT including LA for non-specific CLBP to identify the potential benefits. Methods: The electronic databases MEDLINE (PubMed), Embase (Ovid), the Cochrane Central Register of Controlled Trials (CENTRAL), Korean medical databases (KoreaMed, KMBASE, KISS, NDSL, KISTI, OASIS), the Chinese database (CNKI), and Japanese databases (CiNII, J-STAGE) are recommended. Results: Randomized controlled trials in LLLT including LA should be included in the searches. All data synthesis and subgroup analyses should be conducted using a Review Manager software. The Cochrane risk of bias tool can be used to evaluate methodological quality of the studies. A risk ratio or mean difference with a 95% confidence interval will show the effects of LLLT including LA. Conclusion: The primary outcome would be pain intensity and functional status/disability due to low back pain. The secondary outcome would be a global measurement of recovery or improvement, quality of life and adverse event.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.495-503
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• 2017

Operators of nuclear power plants may not be equipped with sufficient information during a loss-of-coolant accident (LOCA), which can be fatal, or they may not have sufficient time to analyze the information they do have, even if this information is adequate. It is not easy to predict the progression of LOCAs in nuclear power plants. Therefore, accurate information on the LOCA break position and size should be provided to efficiently manage the accident. In this paper, the LOCA break size is predicted using a cascaded fuzzy neural network (CFNN) model. The input data of the CFNN model are the time-integrated values of each measurement signal for an initial short-time interval after a reactor scram. The training of the CFNN model is accomplished by a hybrid method combined with a genetic algorithm and a least squares method. As a result, LOCA break size is estimated exactly by the proposed CFNN model.

• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.838-845
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• 2018

Objective To investigate the effect of a rehabilitation program in terms of De Morton Mobility Index (DEMMI) score, in hematologic cancer patients after chemotherapy. Methods Hematologic cancer patients admitted for chemotherapy were reviewed. They received a rehabilitation program during their hospital stay. DEMMI score measurement was performed, before and after rehabilitation. Demographics, diagnosis, chemotherapy information, rehabilitation program duration, mortality, body mass index (BMI), and laboratory test results were collected. For analysis, patients were classified according to diagnosis (multiple myeloma, leukemia, and others), mortality, and additional chemotherapy. Results There was statistically significant improvement in DEMMI score of 10.1 points (95% confidence interval, 5.9-14.3) after rehabilitation. It was more evident in the multiple myeloma group, and they revealed less mortality. When patients were divided according to mortality, survivors received the program earlier, and in a shorter period than in mortality cases. Although survivors revealed higher initial DEMMI score, improvement after rehabilitation did not differ significantly. Conclusion In hematologic cancer patients, rehabilitation program was effective for recovery from deconditioning, revealing significant increase in DEMMI score. Multiple myeloma patients may be good candidates for rehabilitation. Rehabilitation could be sustained during chemotherapy and for high-risk patients.

• 한국기계가공학회지
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• 제17권6호
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• pp.46-52
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• 2018

Nondestructive evaluation for mechanical degradation of ultrasuper-critical (USC) heat-resistance steel, which is attractive to the next generation of power plants is studied by magnetic reversible permeability. The interrelationship between reversible permeability and high-temperature mechanical degradation has been investigated by precise measurement of permeability nondestructively. Also, the effects of microstructural variation on reversible permeability are discussed. Isothermal aging was observed to coarsen the tempered carbides ($Cr_{23}C_6$), generated the intermetallic phases ($Fe_2W$), and grow rapidly during aging. The dislocation density also decreases steeply within lath interior. The peak to peak interval (PPI) of reversible permeability profile decreased drastically during the initial 500 h aging period, and was thereafter observed to decrease only slightly. The variation in PPI is closely related to the decrease in the number of pinning sites and the degradation in tensile strength.

• Structural Engineering and Mechanics
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• 제77권3호
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• pp.355-368
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• 2021

The time-varying mean (TVM) component of non-stationary wind speeds is commonly extracted utilizing empirical mode decomposition (EMD) in practice, whereas the accuracy of the extracted TVM is difficult to be quantified. To deal with this problem, this paper proposes an approach to identify and extract the optimal TVM from several TVM results obtained by the EMD. It is suggested that the optimal TVM of a 10-min time history of wind speeds should meet both the following conditions: (1) the probability density function (PDF) of fluctuating wind component agrees well with the modified Gaussian function (MGF). At this stage, a coefficient p is newly defined as an evaluation index to quantify the correlation between PDF and MGF. The smaller the p is, the better the derived TVM is; (2) the number of local maxima of obtained optimal TVM within a 10-min time interval is less than 6. The proposed approach is validated by a numerical example, and it is also adopted to extract the optimal TVM from the field measurement records of wind speeds collected during a sandstorm event.

• Advances in concrete construction
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• 제11권2호
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• pp.141-149
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• 2021

This study is a basic research for evaluating the buildability of cementitious materials for three-dimensional (3D) printing. In the cement paste step, the thixotropy behavior according to the resting time, which represents the time interval between each layer, was analyzed. In addition, the relationship between the thixotropy behavior and 3D concrete printing buildability was derived by proposing a measurement method that simulates the 3D concrete printing buildup process. The analysis of the tendency of the thixotropy behavior according to the resting time revealed that the area of the hysteresis loop (AHyst) showed a tendency to increase and then converge as the resting time increased, which means hysteresis loop approach critical resting time for sufficient buildability. In the thixotropy behavior analysis that simulates the 3D concrete printing buildup process, the buildup ratio, which is the recovery rate of the shear stress, showed a tendency to increase and then converge as the resting time increased, which are similar results like hysteresis loop. It was concluded that AHyst and the buildup ratio can be used as parameters for determining the resting time, and they have close relationships with 3D concrete printing buildability.

• Physical Therapy Rehabilitation Science
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• 제11권1호
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• pp.78-87
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• 2022

Objective: The purpose of this study was to investigate the effect of high-intensity complex exercise program using whole-body vibration (WBV) and respiratory resistance on pain and dysfunction, psychosocial level, balance ability, and pulmonary function in low back pain (LBP) patients with high obesity. Design: A randomized controlled trial Methods: A total of 44 LBP patients withhigh obesity (body mass index, BMI≥30kg/m²) were randomly assigned to an experimental group (n=22) and a control group (n=22). Both groups underwent a lumbar stabilization exercise program. In addition, the experimental group implemented the high-intensity complex exercise program combined with WBV and respiratory resistance. In order to compare the effects depending on the intervention methods, numeric pain rating scale (NRPS), Roland-Morris disability questionnaire (RMDQ), fear-avoidance beliefs questionnaire (FABQ), balance ability, and pulmonary function were used for measurement. Results: Both groups showed significant differences in NRPS, RMDQ, FABQ, balance ability before and after intervention (p<0.05). In addition, the experimental groupshowed significant difference in the amount of change in RMDQ, balance ability and pulmonary function values than the control group (p<0.05). Conclusions: High-intensity complex exercise program using WBV and respiratory resistance has been proven to be an effective and clinically useful method to decrease dysfunction, increase balance ablilty, and pulmonary function for LBP patients with high obesity.

• Child Health Nursing Research
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• 제29권1호
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• pp.24-36
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• 2023

Purpose: This systematic literature review and meta-analysis explored extended reality (XR)-based pediatric nursing simulation programs and analyzed their effectiveness. Methods: A literature search was conducted between May 1 and 30, 2022 in the following electronic databases: MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and CINAHL. The search period was from 2000 to 2022. In total, 6,095 articles were reviewed according to the inclusion and exclusion criteria, and 14 articles were selected for the final content analysis and 10 for the meta-analysis. Data analysis was performed using descriptive statistics and the Comprehensive Meta-Analysis program. Results: XR-based pediatric nursing simulation programs have increased since 2019. Studies using virtual reality with manikins or high-fidelity simulators were the most common, with six studies. The total effect size was statistically significant at 0.84 (95% confidence interval=0.50-1.19, z=4.82, p<.001). Conclusion: Based on the findings, we suggest developing standardized guidelines for the operation of virtual pediatric nursing simulation education and practice. Simultaneously, the application of more sophisticated research designs for effect measurement and the combined applications of various virtual simulation methods are needed to validate the most effective simulation methodology.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.149-150
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• 2022

In Korea, there is no clearly established technology for diagnosing and evaluating the damage depth of concrete structures created by fire. There have been cases of repairing, reinforcing, and demolishing degraded structures without diagnosing the damage depth. The commonly used phenolphthalein-based carbonate thickness measurement does not satisfy the complete disappearance condition of Ca(OH)₂ in the interval where the relatively stationary flow declines after exposure to high temperatures. Even a small amount of Portlandite[Ca(OH)₂] reacts with a red color, and the damage depth is misjudged. It was confirmed by X-ray diffraction and scanning electron microscope that Ca(OH)₂ existed from 300℃ to 500℃ where the residual compressive strength decreased.