• The Korean Journal of Physiology and Pharmacology
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• 제28권3호
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• pp.253-264
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• 2024

Chronic neuropathic pain (CNP) is a complex condition often arising from neural maladaptation after nerve injury. Understanding CNP complications involves the intricate interplay between brain-heart dynamics, assessed through quantitative electroencephalogram (qEEG) and heart rate variability (HRV). However, insights into their interaction in chronic pain are limited. Resting EEG and simultaneous electrocardiogram (lead II) of the participants were recorded for qEEG and HRV analysis. Correlations between HRV and qEEG parameters were calculated and compared with age, sex, and body mass index (BMI)-matched controls. CNP patients showed reduced HRV and significant increases in qEEG power spectral densities within delta, theta, and beta frequency ranges. A positive correlation was found between low frequency/high frequency (LF/HF) ratio in HRV analysis and theta, alpha, and beta frequency bands in qEEG among CNP patients. However, no significant correlation was observed between parasympathetic indices and theta, beta bands in qEEG within CNP group, unlike age, sex, and BMI-matched healthy controls. CNP patients display significant HRV reductions and distinctive qEEG patterns. While healthy controls exhibit significant correlations between parasympathetic HRV parameters and qEEG spectral densities, these relationships are diminished or absent in CNP individuals. LF/HF ratio, reflecting sympathovagal balance, correlates significantly with qEEG frequency bands (theta, alpha, beta), illuminating autonomic dysregulation in CNP. These findings emphasize the intricate brain-heart interplay in chronic pain, warranting further exploration.

• 대한조선학회논문집
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• 제61권1호
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• pp.8-18
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• 2024

The present study concerns reduced order modeling of a marine diesel engine, which can be used for outlier detection in status monitoring and carbon intensity index calculation. Principal Component Analysis (PCA) is introduced for the reduced order modeling, focusing on the feasibility of detecting and treating nonlinear variables. By cross-correlation, it is found that there are seven non-linear data channels among 23 data channels, i.e., fuel mode, exhaust gas temperature after the turbocharger, and cylinder coolant temperatures. The dataset is handled so that the mean is located at the nominal continuous rating. Polynomial presentation of the dataset is also applied to reflect the linearity between the engine speed and other channels. The first principal mode shows strong effects of linearity of the most data channels to show the linearity of the system. The non-linear variables are effectively explained by other modes. second mode concerns the temperature of the cylinder cooling water, which shows small correlation with other variables. The third and fourth modes correlates the fuel mode and turbocharger exhaust gas temperature, which have inferior linearity to other channels. PCA is proven to be applicable to data given in binary type of fuel mode selection, as well as numerical type data.

• 지역연구
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• 제40권2호
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• pp.21-38
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• 2024

지역 인구와 경지면적 간의 상호작용을 이해하는 것은 지역 경제 활성화와 농업의 지속가능성 향상을 위해 중요하다. 기존의 연구들은 지역의 인구이동이나 경지면적 변화 각각의 주제에 중점을 두었으며, 이들의 상호작용에 관한 연구는 미흡했다. 또한, 새로운 노동 공급원인 외국인 근로자의 증가를 대상으로 한 지역 단위의 정량적 연구도 부족했다. 이에 본 연구에서는 지역의 인구 변화, 경지면적, 그리고 외국인 근로자 수 변화의 상호작용을 패널 자기 상관 모형(Panel Vector Auto Regression Model)을 활용하여 분석하였다. 분석 결과, 지역의 인구유입률과 경지면적은 서로에게 부정적인 영향을 발생시키지만, 농업부문의 외국인 근로자 증가는 경지면적을 증가시키는 것으로 나타났다. 또한, 밭 면적의 증가는 외국인 근로자를 증가시키는 것으로 나타났다. 이러한 결과는 지역의 인구감소와 경지면적 감소 현상이 상호영향을 미치고 있으며 외국인 근로자의 유입이 농촌지역의 구조적 문제해결에 긍정적인 영향을 미칠 가능성이 있음을 시사한다.

• Tribology and Lubricants
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• 제40권2호
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• pp.39-46
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• 2024

The Morton effect (ME) is an instability phenomenon occurring in rotating machineries supported by fluid film bearings and is induced by the thermal deformation of the overhung mass, which is a part of the rotating shaft. Herein, we describe the ME during the high-speed balancing test of a 20 MW class steam turbine. Additionally, to predict the rotating speed at which the ME occurs, we apply the sensitivity vector theory for the steam turbine. During the operation of the steam turbine, we observe a continuous increase in vibration and hysteresis near the rated speed, which is typical of the ME. Increasing the temperature of the lubricating oil supplied to the bearings from 40 to 60℃ suppresses the occurrence of the ME. The rotordynamic analysis for the steam turbine suggests the existence of a mode in which the overhung mass undergoes significant deformation near the rated speed, and we presume that such a mode will increase the occurrence of the ME. The predicted rotating speed of ME occurrence, obtained through the sensitivity vector method, correlates with the test results. Moreover, increasing the temperature of the supplied lubricating oil mitigates the occurrence of ME by reducing the sensitivity between the temperature deviation vector and unbalance mass vector.

• Korean Journal of Radiology
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• 제1권2호
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• pp.110-113
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• 2000

Objective: The purpose of this study was to determine, when measuring prostate volume by TRUS, whether height is more accurately determined by transaxial or midsagittal scanning. Materials and Methods: Sixteen patients who between March 1995 and March 1998 underwent both preoperative TRUS and radical prostatectomy for prostate cancer were included in this study. Using prolate ellipse volume calculation (height × length × width × 𝜋/6), TRUS prostate volume was determined, and was compared with the measured volume of the specimen. Results: Prostate volume measured by TRUS, regardless of whether height was determined transaxially or midsagittally, correlated closely with real specimen volume. When height was measured in one of these planes, a paired t test revealed no significant difference between TRUS prostate volume and real specimen volume (p = .411 and p = .740, respectively), nor were there significant differences between the findings of transaxial and midsagittal scanning (p = .570). A paired sample test, however, indicated that TRUS prostate volumes determined transaxially showed a higher correlation coefficient (0.833) and a lower standard deviation (9.04) than those determined midsagittally (0.714 and 11.48, respectively). Conclusion: Prostate volume measured by TRUS closely correlates with real prostate volume. Furthermore, we suggest that when measuring prostate volume in this way, height is more accurately determined by transaxial than by midsagittal scanning.

• 아태비즈니스연구
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• 제14권4호
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• pp.431-444
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• 2023

Purpose - This study applies the traditional Structure-Conduct-Performance (SCP) model from industrial organization theory to investigate the relationship between market structure and performance in China's banking industry. Design/methodology/approach - For analysis, financial data from the People's Bank of China's "China Financial Stability Report" and financial reports of 6 state-owned banks and 11 joint-stock banks for the period 2010 to 2021 were collected to create a balanced panel dataset. The study employs panel fixed-effects regression analysis to assess the impact of changes in market structure and ownership structure on performance variables including return on asset, profitability, costs, and non-performing loan ratios. Findings - Empirical findings highlight significant differences in the effects of market structure between state-owned and joint-stock banks. Notably, increased market competition positively correlates with higher profits for state-owned banks and with lower costs for joint-stock banks. Research implications or Originality - State-owned banks demonstrate larger scale and stability, yet they struggle to respond effectively to market shifts. Conversely, joint-stock banks face challenges in raising profitability against competitive pressures. Additionally, the study emphasizes the importance for Chinese banks to strengthen risk management due to the increase of non-performing loans with competition. The results provide insights into reform policies for Chinese banks regarding the involvement of private sector in the context of market liberalization process in China.

• Journal of Korean Neurosurgical Society
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• 제67권3호
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• pp.364-375
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• 2024

Objective : Kinesin family member C1 (KIFC1), a non-essential kinesin-like motor protein, has been found to serve a crucial role in supernumerary centrosome clustering and the progression of several human cancer types. However, the role of KIFC1 in glioma has been rarely reported. Thus, the present study aimed to investigate the role of KIFC1 in glioma progression. Methods : Online bioinformatics analysis was performed to determine the association between KIFC1 expression and clinical outcomes in glioma. Immunohistochemical staining was conducted to analyze the expression levels of KIFC1 in glioma and normal brain tissues. Furthermore, KIFC1 expression was knocked in the glioma cell lines, U251 and U87MG, and the functional roles of KIFC1 in cell proliferation, invasion and migration were analyzed using cell multiplication, wound healing and Transwell invasion assays, respectively. The autophagic flux and expression levels matrix metalloproteinase-2 (MMP2) were also determined using imaging flow cytometry, western blotting and a gelation zymography assay. Results : The results revealed that KIFC1 expression levels were significantly upregulated in glioma tissues compared with normal brain tissues, and the expression levels were positively associated with tumor grade. Patients with glioma with low KIFC1 expression levels had a more favorable prognosis compared with patients with high KIFC1 expression levels. In vitro, KIFC1 knockdown not only inhibited the proliferation, migration and invasion of glioma cells, but also increased the autophagic flux and downregulated the expression levels of MMP2. Conclusion : Upregulation of KIFC1 expression may promote glioma progression and KIFC1 may serve as a potential prognostic biomarker and possible therapeutic target for glioma.

• 반도체디스플레이기술학회지
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• 제23권1호
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• pp.12-18
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• 2024

The accelerated pace of climate crisis due to continuous industrialization and greenhouse gas emissions necessitates sustainable solutions that simultaneously address mitigation and adaptation to climate change. Naturebased Solutions (NbS) have gained prominence as viable approaches, with Green Infrastructure being a representative NbS. Green Infrastructure involves securing green spaces within urban areas, providing diverse climate adaptation functions such as removal of various air pollutants, carbon sequestration, and isolation. The proliferation of Green Infrastructure is influenced by the quantification of improvement effects related to various projects. To support decision-making by assessing the climate vulnerability of Green Infrastructure, the U.S. Department of Agriculture (USDA) has developed i-Tree Tools. This study proposes a comprehensive evaluation approach for climate change adaptation types by quantifying the climate adaptation performance of urban Green Infrastructure. Using i-Tree Canopy, the analysis focuses on five urban green spaces covering more than 30 hectares, considering the tree ratio relative to the total area. The evaluation encompasses aspects of thermal environment, aquatic environment, and atmospheric environment to assess the overall eco-friendliness in terms of climate change adaptation. The results indicate that an increase in the tree ratio correlates with improved eco-friendliness in terms of thermal, aquatic, and atmospheric environments. In particular, it is necessary to prioritize consideration of the water environment sector in order to realize climate change adaptive green infrastructure, such as increasing green space in urban areas, as it has been confirmed that four out of five target sites are specialized in improving the water environment.

• 문화기술의 융합
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• 제10권3호
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• pp.405-411
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• 2024

본 연구의 목적은 노인의 디지털 기기 활용이 성공적 노화에 미치는 영향 관계에서 사회지지의 매개효과를 검증하는 것이다. 이를 위해 D시와 K시에 소재한 노인복지시설을 이용하는 노인 363명이 설문조사에 참여하였으며, 수집된 자료는 SPSS 22.0과 PROCESS Macro v3.5 프로그램을 활용하여 분석하였다. 분석결과, 노인의 디지털 기기 활용은 사회지지 및 성공적 노화와 정적 상관관계를 가지는 것으로 나타나, 디지털 기기 활용 수준이 높을수록, 사회지지와 성공적 노화 수준이 높은 것으로 확인되었다. 또한, 노인의 디지털 기기 활용과 사회지지는 성공적 노화에 통계적으로 유의한 정적 영향을 미치는 것으로 나타났으며, 사회지지는 노인의 디지털 기기 활용과 성공적 노화와의 관계에 유의한 매개효과가 있는 것으로 확인되었다. 마지막으로, 본 연구결과를 바탕으로, 노인의 성공적 노화를 증진시키기 위한 실천적 함의와 추후 연구에 관한 제언을 제시하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제13권2호통권54호
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• pp.115-121
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• 2009

본 연구에서는 동적 가속도 데이터를 사용하는 신호기반 손상진단 알고리즘으로 ARX 모델을 제시하였다. ARX 모델은 구조물의 두 지점에서 계측된 가속도 데이터를 입력과 출력의 두 세트 신호로 보고, 두 세트 가속도 데이터의 상관관계를 설정한다. 구조물 손상은 계측한 데이터와 전달함수인 ARX 모델로 예측한 데이터의 차이인 시간이력 잔차를 사용하여 통계적으로 탐색하였다. 시간이력 잔차의 정규분포함수를 구하고, 그 통계적 특성치를 계산하여 손상 평가에 사용하였다. 손상 전후의 정규분포함수를 비교하여 손상을 탐색하기 위하여 세 가지 손상지수를 제시하였다. 손상지수의 통계적 평가를 위해 실내실험을 수행하였고, 제안한 알고리즘의 효율성을 검증하고 제한점을 검토하였다.