• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.701-709
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• 2021

The paper aims at improving the understanding and mitigating the effects of tunnel fires that may breakout due to the burning fuel and/or explosion within the tunnel. This study particularly focuses on the behavior of the commonly used horse shoe geometry of tunnel systems. The problem has been obtained using an adequate well-established program incorporating the Lagrangian approach. A transient-thermo-coupled static structural analysis is carried out. The effects of radiation and convection to the outer walls of the tunnel is studied. The paper also presents the impact of the hazard on the structural integrity of the tunnel. A methodology is proposed to study the tunnel fire using a model which uses equivalent steel sheet to represent the presence of reinforcements to improve the computational efficiency with adequate validation. A parametric study has been carried out and the effect of suitable lining property for mitigating the fire hazard is arrived at. Detailed analysis is done for the threshold limits of the properties of the lining material to check if it is acceptable in all aspects for the integrity of the tunnel. The study may prove useful for developing insights for ensuring tunnel fire safety. To conduct such studies experimentally are tremendously costly but are required to gain confidence. But, scaled models, as well as loading and testing conditions, cannot be studied by many trials experimentally as the cost will shoot up sharply. In this context, the results obtained from such computational studies with a feasible variation of various combinations of parameters may act as a set of guidelines to freeze the adequate combination of various parameters to conduct one or two costly experiments for confidence building.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.12
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• pp.4292-4307
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• 2021

For the research field of night infrared surveillance video, the target imaging in the video is easily affected by the light due to the characteristics of the active infrared camera and the classical ViBe algorithm has some problems for moving target extraction because of background misjudgment, noise interference, ghost shadow and so on. Therefore, an improved ViBe algorithm (I-ViBe) for moving target extraction in night infrared surveillance video is proposed in this paper. Firstly, the video frames are sampled and judged by the degree of light influence, and the video frame is divided into three situations: no light change, small light change, and severe light change. Secondly, the ViBe algorithm is extracted the moving target when there is no light change. The segmentation factor of the ViBe algorithm is adaptively changed to reduce the impact of the light on the ViBe algorithm when the light change is small. The moving target is extracted using the region growing algorithm improved by the image entropy in the differential image of the current frame and the background model when the illumination changes drastically. Based on the results of the simulation, the I-ViBe algorithm proposed has better robustness to the influence of illumination. When extracting moving targets at night the I-ViBe algorithm can make target extraction more accurate and provide more effective data for further night behavior recognition and target tracking.

• Composites Research
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• v.34 no.6
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• pp.412-420
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• 2021

In this study, we measure the initial electrical conductivity of SCF/rubber specimens and SCF/rubber specimens with nickel particles respectively. The corresponding electrical conductivity with compressive strain on the specimens is also measured. Through this experiment, we observed the effects of the volume fraction of carbon fiber, nickel particles and external strain on the electrical conductivity. Experiments show that even a small difference in the volume fraction of SCF plays a major role in the change of the electrical conductivity and that the piezoresistivity increases due to fiber reorientation respond to external strain. In addition, the nickel particles contribute to improving the electrical conductivity in specimens with carbon fibers above the threshold volume fraction. It was confirmed that there is an effect of offsetting the increment in the piezoresistivity caused by the reorientation of carbon fibers according to external strain.

• The Korean Journal of Pain
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• v.35 no.4
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• pp.383-390
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• 2022

Background: The treatment of trigeminal neuralgia remains a challenging issue. Stem cells from human exfoliated deciduous teeth (SHED) provide optimized therapy for chronic pain. This study aimed to investigate the mechanisms underlying the attenuation of trigeminal neuralgia by SHED. Methods: Trigeminal neuralgia was induced by chronic constriction injury of the infraorbital nerve. The mechanical threshold was assessed after model establishment and local SHED transplantation. Endoplasmic reticulum (ER) morphology and Caspase12 expression in trigeminal ganglion (TG) was evaluated as well. BiP expression was observed in PC12 cells induced by tunicamycin. Results: The local transplantation of SHED could relieve trigeminal neuralgia in rats. Further, transmission electron microscopy revealed swelling of the ER in rats with trigeminal neuralgia. Moreover, SHED inhibited the tunicamycin-induced up-regulated expression of BiP mRNA and protein in vitro. Additionally, SHED decreased the up-regulated expression of Caspase12 mRNA and protein in the TG of rats caused by trigeminal neuralgia after chronic constriction injury of the infraorbital nerve mode. Conclusions: This findings demonstrated that SHED could alleviate pain by relieving ER stress which provide potential basic evidence for clinical pain treatment.

• Journal of Trauma and Injury
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• v.35 no.1
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• pp.25-33
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• 2022

Purpose: The scoring system for traumatic liver injury (SSTLI) was developed in 2015 to predict mortality in patients with polytraumatic liver injury. This study aimed to validate the SSTLI as a prognostic factor in patients with polytrauma and liver injury through a generalized estimating equation analysis. Methods: The medical records of 521 patients with traumatic liver injury from January 2015 to December 2019 were reviewed. The primary outcome variable was in-hospital mortality. All the risk factors were analyzed using multivariate logistic regression analysis. The SSTLI has five clinical measures (age, Injury Severity Score, serum total bilirubin level, prothrombin time, and creatinine level) chosen based on their predictive power. Each measure is scored as 0-1 (age and Injury Severity Score) or 0-3 (serum total bilirubin level, prothrombin time, and creatinine level). The SSTLI score corresponds to the total points for each item (0-11 points). Results: The areas under the curve of the SSTLI to predict mortality on post-traumatic days 0, 1, 3, and 5 were 0.736, 0.783, 0.830, and 0.824, respectively. A very good to excellent positive correlation was observed between the probability of mortality and the SSTLI score (γ=0.997, P<0.001). A value of 5 points was used as the threshold to distinguish low-risk (<5) from high-risk (≥5) patients. Multivariate analysis using the generalized estimating equation in the logistic regression model indicated that the SSTLI score was an independent predictor of mortality (odds ratio, 1.027; 95% confidence interval, 1.018-1.036; P<0.001). Conclusions: The SSTLI was verified to predict mortality in patients with polytrauma and liver injury. A score of ≥5 on the SSTLI indicated a high-risk of post-traumatic mortality.

• The Korean Journal of Pain
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• v.35 no.3
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• pp.271-279
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• 2022

Background: Inflammation is known to underlie the pathogenesis in neuropathic pain. This study investigated the anti-inflammatory and neuroprotective mechanisms involved in antinociceptive effects of co-administration of acetaminophen and L-carnosine in chronic constriction injury (CCI)-induced peripheral neuropathy in male Wistar rats. Methods: Fifty-six male Wistar rats were randomly divided into seven experimental groups (n = 8) treated with normal saline/acetaminophen/acetaminophen + L-carnosine. CCI was used to induce neuropathic pain in rats. Hyperalgesia and allodynia were assessed using hotplate and von Frey tests, respectively. Investigation of spinal proinflammatory cytokines and antioxidant system were carried out after twenty-one days of treatment. Results: The results showed that the co-administration of acetaminophen and L-carnosine significantly (P < 0.001) increased the paw withdrawal threshold to thermal and mechanical stimuli in ligated rats compared to the ligated naïve group. There was a significant (P < 0.001) decrease in the levels of nuclear factor kappa light chain enhancer B cell inhibitor, calcium ion, interleukin-1-beta, and tumour necrotic factor-alpha in the spinal cord of the group coadministered with acetaminophen and L-carnosine compared to the ligated control group. Co-administration with acetaminophen and L-carnosine increased the antioxidant enzymatic activities and reduced the lipid peroxidation in the spinal cord. Conclusions: Co-administration of acetaminophen and L-carnosine has anti-inflammatory effects as a mechanism that mediate its antinociceptive effects in CCI-induced peripheral neuropathy in Wistar rat.

• Journal of Practical Engineering Education
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• v.14 no.2
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• pp.413-423
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• 2022

The purpose of this study is to analyze the role of the job competency assessor who assess achievement of job performance ability based on NCS (educational training, qualifications, field experience, etc.) through competency assessment. For this purpose, job analysis including development and verification of the job model and selection of core task are conducted. As a result, main duties of the job competency assessor are to understand the NCS based assessment principle, establish an assessment plan, design and develop assessment tools, assess competence, provide feedback and re-assessment, record and manage assessment result, verify the internal assessment result, establish the RPL (recognition of prior learning) plan, implement the RPL and verify the RPL assessment result, and 48 task are derived. In addition, a total of 21 core tasks are derived based on the threshold value multiplied by the importance and difficulty of the task for each duty. Based on this, implications for job analysis of the job competency assessor are presented.

• Smart Structures and Systems
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• v.31 no.4
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• pp.421-436
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• 2023

This paper presents a vibration displacement measurement and damage identification method for a space truss structure from its vibration videos. Features from Accelerated Segment Test (FAST) algorithm is combined with adaptive threshold strategy to detect the feature points of high quality within the Region of Interest (ROI), around each node of the truss structure. Then these points are tracked by Kanade-Lucas-Tomasi (KLT) algorithm along the video frame sequences to obtain the vibration displacement time histories. For some cases with the image plane not parallel to the truss structural plane, the scale factors cannot be applied directly. Therefore, these videos are processed with homography transformation. After scale factor adaptation, tracking results are expressed in physical units and compared with ground truth data. The main operational frequencies and the corresponding mode shapes are identified by using Subspace Stochastic Identification (SSI) from the obtained vibration displacement responses and compared with ground truth data. Structural damages are quantified by elemental stiffness reductions. A Bayesian inference-based objective function is constructed based on natural frequencies to identify the damage by model updating. The Success-History based Adaptive Differential Evolution with Linear Population Size Reduction (L-SHADE) is applied to minimise the objective function by tuning the damage parameter of each element. The locations and severities of damage in each case are then identified. The accuracy and effectiveness are verified by comparison of the identified results with the ground truth data.

• Journal of Korean Neurosurgical Society
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• v.66 no.4
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• pp.409-417
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• 2023

Objective : The association between boule (BOLL) and endothelin receptor type A (EDNRA) loci and intracranial aneurysm (IA) formation has been reported via genome-wide association studies. We sought to identify genome-wide interactions involving BOLL and EDNRA loci for IA in a Korean adult cohort. Methods : Genome-wide pairwise interaction analyses of BOLL and EDNRA involving 250 patients with IA and 296 controls were performed using the additive effect model after adjusting for confounding factors. Results : Among 512575 single-nucleotide polymorphisms (SNPs), 23 and 11 common SNPs suggested a genome-wide interaction threshold (p<1.25×10^-8) involving rs700651 (BOLL) and rs6841581 (EDNRA). Rather than singe SNP effect of BOLL or EDNRA on IA development, they showed a synergistic effect on IA formation via multifactorial pair-wise interactions. The rs1105980 of PTCH1 gene showed the most significant interaction with rs700651 (natural log-transformed odds ratio [lnOR], 1.53; p=6.41×10^-11). The rs74585958 of RYK gene interacted strongly with rs6841581 (lnOR, -19.91; p=1.64×10^-9). Although, there was no direct interaction between BOLL and EDNRA variants, two EDNRA-interacting gene variants of TNIK (rs11925024 and rs1231) and FTO (rs9302654), and one BOLL-interacting METTL4 gene variant (rs549315) exhibited marginal interaction with BOLL gene. Conclusion : BOLL or EDNRA may have a synergistic effect on IA formation via multifactorial pair-wise interactions.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.182-182
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• 2020

최근 지구 온난화나 기상이변으로 인해 세계각지에서 많은 자연재해가 발생하고 있고 우리나라도 최근 전국 각지에서 국지성호우에 의한 많은 피해가 발생하고 있다. 특히 국지성호우로 인해 발생하는 산간지역의 토석류는 많은 재산피해를 일으키고 있다. 최근 토석, 토사, 혹은 부유 잡목 등의 유출로 인한 피해를 막기 위해 많은 사방댐을 축조하고 있으나 표면침식에 의해서 유출되는 토석량 혹은 토사량을 정확히 예측하지 못한다면 축조된 사방댐은 금방 제구실을 못할 수 있거나 혹은 과대 설계 및 시공되어 건설비를 낭비할 수 있다. 따라서 최적의 사방댐 건설을 위해 정확한 토석량의 산정은 매우 중요한 전제조건이라 할 수 있다. 본 연구에서는 강원도 인제군 산간지역 4곳의 사방댐유역에 대해 토석량 예측모형 MSDPM(Multi-Sequence Debris Prediction Model)과 LADMP(Los Angeles District Method for Prediction of sediments yield)를 이용하여 산정한 토석량과 실제 준설량을 비교하였다. 이를 위해 강원 산간지역에 맞도록 예측모형을 보정하였으며 토석류 유발 강우강도(Threshold Maximum 1-hr Rainfall Intensity)와 토석류 유발 최소강우량(Total Minimum Rainfall Amount)개념을 도입하여 예측모형식을 적용하였다. 위 식이 갖고 있는 대표적 특징 중 하나인 산불계수를 사용해야 하지만 본 연구지역은 산불 피해규모가 미미하여 산불의 영향은 고려하지 않고 토석량을 산정하였다. 두 예측모형의 계산결과와 실제 준설량을 비교해본 결과, MSDPM의 결과가 LADMP의 결과보다 준설량과 더 일치하는 것으로 나타났다. 실제 준설량과 MSDPM의 계산결과는 평균 17.37%의 차이를 나타냈고 LADMP의 계산결과는 평균 41.87%의 차이를 나타냈다. 본 연구에서 사용된 토석량 예측 모형은 앞으로 많은 산지유역의 토석량 예측에 사용이 가능 할 것으로 판단된다. 하지만 본 연구에서 사용된 자료의 제한성 때문에 앞으로 많은 실측 준설자료를 통하여 예측모형식을 보정하는 작업이 우선되어야 할 것으로 판단된다. 이를 위해서 많은 산지유역의 토석량을 장시간 실측하여 데이터를 축적하고 이를 사용하여 다양한 토석량 예측모형을 검보정하는 노력이 필요할 것으로 판단된다.