• Geomechanics and Engineering
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• v.23 no.1
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• pp.1-13
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• 2020

To give a solution for seismic stability of tunnel faces subjected to earthquake ground shakings, the pseudo-dynamic approach is originally introduced to analyze tunnel face stability in this study. In the light of the upper-bound theorem of limit analysis, an advanced three-dimensional mechanism combined with pseudo-dynamic approach is proposed. Based on this mechanism, the required support pressure on tunnel face can be obtained by equaling external work rates to the internal energy dissipation and implementing an optimization searching procedure related to time. Both time and space feature of seismic waves are properly accounted for in the proposed mechanism. For this reason, the proposed mechanism can better represent the actual influence of seismic motion and has a remarkable advantage in evaluating the effects of vertical seismic acceleration, soil amplification factor, seismic wave period and initial phase difference on tunnel face stability. Furthermore, the pseudo-dynamic approach is compared with the pseudo-static approach. The difference between them is illustrated from a new but understandable perspective. The comparison demonstrates that the pseudo-static approach is a conservative method but still could provide precise enough results as the pseudo-dynamic approach if the value of seismic wavelengths is large or the height of soil structures is small.

• Steel and Composite Structures
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• v.1 no.1
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• pp.145-158
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• 2001

An experimental study was conducted to evaluate the effects of loading sequence and lateral bracing on the behavior of reduced beam section (RBS) steel moment frame connections. Four full-scale moment connections were cyclically tested-two with a standard loading history and the other two with a near-fault loading history. All specimens reached at least 0.03 radian of plastic rotation without brittle fracture of the beam flange groove welds. Two specimens tested with the nearfault loading protocol reached at least 0.05 radian of plastic rotation, and both experienced smaller buckling amplitudes at comparable drift levels. Energy dissipation capacities were insensitive to the types of loading protocol used. Adding a lateral bracing near the RBS region produced a higher plastic rotation; the strength degradation and buckling amplitude were reduced. A non-linear finite element analysis of a one-and-a-half-bay beam-column subassembly was also conducted to study the system restraint effect. The study showed that the axial restraint of the beam could significantly reduce the strength degradation and buckling amplitude at higher deformation levels.

• Structural Engineering and Mechanics
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• v.54 no.3
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• pp.393-417
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• 2015

In this paper an 8-node quadrilateral assumed stress hybrid Mindlin plate element with $39{\beta}$ is presented. The formulation is based on complementary energy principle. The proposed element is free of shear locking and is capable of passing all the patch tests, especially the non-zero constant shear enhanced patch test. To accomplish this purpose, special attention is devoted to selecting boundary displacement interpolation and stress approximation in domain. The arbitrary order Timoshenko beam function is successfully used to derive the boundary displacement interpolation. According to the equilibrium equations, an appropriate stress approximation is rationally derived. Particularly, in order to improve element's accuracy, the assumed stress field is derived by employing $39{\beta}$ rather than conventional $21{\beta}$. The resulting element can be adopted to analyze both moderately thick and thin plates, and the convergence for the very thin case can be ensured theoretically. Excellent element performance is demonstrated by a wide of experimental evaluations.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1729-1738
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• 2014

The offline verification of state of charge estimation, power estimation, fault diagnosis and emergency control of battery management system (BMS) is one of the key technologies in the field of electric vehicle battery system. It is difficult to test and verify the battery management system software in the early stage, especially for algorithms such as system state estimation, emergency control and so on. This article carried out the virtual environment modeling for verification of battery management system. According to the input/output parameters of battery management system, virtual environment is determined to run the battery management system. With the integration of the developed BMS model and the external model, the virtual environment model has been established for battery management system in the vehicle's working environment. Through the virtual environment model, the effectiveness of software algorithm of BMS was verified, such as battery state parameters estimation, power estimation, fault diagnosis, charge and discharge management, etc.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.190-190
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• 2010

Zinc oxide is the most attractive material due to the large direct band gap (3.37 eV), excellent chemical and thermal stability, and large exciton binding energy (60 meV). Recently, ZnO nanorods were used as the high efficient antireflection coating layer of solar cells based on silicon (Si). In this reports, we studied the effects of rapid thermal annealing (RTA) treatment on optical properties of ZnO nanorods. For fabrication of ZnO nanorods, there are many methods such as hydrothermal method, sol-gel method, and metal organic chemical vapor deposition method. Among of them, we used the conventional wet chemical method which is simple and low temperature growth. In order to synthesize the ZnO nanorods, the ZnO films were deposited on Si substrate by RF magnetron sputtering at room temperature and the samples were dipped to aqua solution containing the zinc nitrate and hexamethylentetramines (HMT). The synthesis process was achieved in keeping with temperature of $90-95^{\circ}C$ and under constant stirring. The morphology of ZnO nanorods on glass and Si was characterized by scanning electron microscopy. For the analysis of antireflection performance, the reflectance and transmittance were measured by spectrophotometer. And for analyzing the effects of RTA treatment on ZnO nanorods, crystalline properties were investigated by X-ray diffraction measurements and optical properties was estimated by photoluminescence spectra.

• The Journal of Internal Korean Medicine
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• v.24 no.2
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• pp.395-401
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• 2003

Facial nerver paralysis is classified as Supranuclear, Peripheral and Nuclear. It is mostly Spontaneous Peripheral Facial Paralysis(Bell's palsy) or Supranuclear Paralysis by C.V.A, but Nuclear Facial Nerve Paralysis is rarely reported. We treated a 64-years-old female patient who had 7-years history of C.V.A with hypertension and heart disease, and complained of these symptoms; left facial palsy, ocular dysmetria, diplopia, and right extremity weakness. We diagnosed as direct attack from the wind pathogen(風邪入中) with deficiency of both Gi(Qi, vital energy) and blood(氣血雨虛), and employed Oriental medical treatments; herb-medication, acupuncture and moxa therapy. The result was relatively acceptable. So We report this case with a brief review of related literatures.

• Journal of Distribution Science
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• v.19 no.1
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• pp.5-15
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• 2021

Purpose: This study explores the types of relational benefits that generate loyalty to room-sharing services among Chinese customers based on the relationship marketing literature. The study also examines the moderating effect of alternative attractiveness on this relationship. Research design, data and methodology: Based on research hypotheses, questionnaires with items measuring the proposed constructs in three dimensions, including relational benefits, alternative attractiveness, and customer loyalty, were designed to test the hypotheses. Data were collected via an online questionnaire of 220 room-sharing service customers in China. Results: Results verify the effects of relational benefits on customers' loyalty to room-sharing services and the mediating effect of alternative attractiveness. More specifically, confidence, social, and safety benefits positively affect customer loyalty to room-sharing services, and alternative attractiveness moderates only the effect of social benefits. Conclusions: The results suggest that room-sharing service providers should concentrate on providing confidence, social, and safety benefits to maintain long-term relationships with customers. This study also provides practical implication for building relationships between channel members in service distribution channels. The study concludes that without customer relationships marketing for managing collaborative and social communication channels, the entire distribution channel might lose out eventually.

• Advances in concrete construction
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• v.12 no.6
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• pp.507-515
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• 2021

To evaluate the influence of slag on the alkalinity of pore solution and microstructure of concrete, this paper performs a leaching experiment on hardened cement-slag pastes (HCSP) slice specimens with different slag content in purified water. The pH value of pore solution, average porosity, morphology, phase composition and Ca/Si of HCSP specimens in the leaching process are measured by solid-liquid extraction, saturated-dried weighing, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray diffraction (XRD). Results shows that the addition of slag can mitigate an increase in porosity and a decrease in Ca/Si of HCSP in the leaching process. Besides, an appropriate slag content can improve the microstructure so as to obtain the optimum leaching resistance of HCSP, which can guarantee the suitable alkalinity of pore solution to prevent a premature corrosion of reinforced bar. The optimum slag content is 40% in HCSP with a water-binder ratio of 0.45, and an excessive slag causes a significant decrease in the alkalinity of pore solution, resulting in a loss of protection on reinforced bar in HCSP.

• Geomechanics and Engineering
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• v.29 no.5
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• pp.523-533
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• 2022

Several prediction model of penetration rate (PR) of tunnel boring machines (TBMs) have been focused on applying to design stage. In construction stage, however, the expected PR and its trends are changed during tunneling owing to TBM excavation skills and the gap between the investigated and actual geological conditions. Monitoring the PR during tunneling is crucial to rescheduling the excavation plan in real-time. This study proposes a sequential prediction method applicable in the construction stage. Geological and TBM operating data are collected from Gunpo cable tunnel in Korea, and preprocessed through normalization and augmentation. The results show that the sequential prediction for 1 ring unit prediction distance (UPD) is R²≥0.79; whereas, a one-step prediction is R²≤0.30. In modeling algorithm, a gradient boosted regression tree (GBRT) outperformed a least square-based linear regression in sequential prediction method. For practical use, a simple equation between the R² and UPD is proposed. When UPD increases R² decreases exponentially; In particular, UPD at R²=0.60 is calculated as 28 rings using the equation. Such a time interval will provide enough time for decision-making. Evidently, the UPD can be adjusted depending on other project and the R² value targeted by an operator. Therefore, a calculation process for the equation between the R² and UPD is addressed.

• The Journal of Korean Medical History
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• v.35 no.2
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• pp.83-88
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• 2022

In East Asian medicine, 'gihyeol(氣血)' and 'hyeolgi(血氣)' are basic terms that can be found everywhere. However, despite its importance, there is no clear definition of the terms. In this paper, we tried to distinguish between 'gihyeol(氣血)' and 'hyeolgi(血氣)' and looked at actual clinical examples that were judged to be consistent with this idea. The terms of East Asian medicine reflect its view of the human body and the origin of this view of the body can be seen as Han's theory of sensitivity. In addition, in East Asian medicine, the human body was understood as having a dualistic structure. Based on the theories of Asian medicine, energy can be understood as qi and blood. Therefore, 'gihyeol(氣血)' and 'hyeolgi(血氣)' are not similar or the same terms, but can be seen as terms to distinguish different internal flows of the human body. This organic view of the human body leads to the 'Hyeonggiron(形氣論)' of Donguibogam, and this 'Hyeonggiron(形氣論)' leads to the 'Hyeonggiron(形氣論)' of Hyungsang Medicine.