• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.53-60
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• 2010

Considering environmental issues and lack of space, it is a necessity to minimize the amount of excavation. Various types of excavation methods are being used in practice. This study proposes a reasonable method for estimating the earth pressure acting on a reinforced wall in front of a excavated slope. The measured data in the field and numerical analyses were used. Results of the study shows that the earth pressure acting on the excavated wall is less than that estimated by Rankine's equations. It was shown that when the excavated slope is used with the reinforced wall, the pressures acting on the reinforced wall can be greatly reduced.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.67-76
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• 2017

In this study, the effect of caisson heel on the active earth pressure is investigated. Using limit analysis method, inclinations of slip surface developed above the heel with different lengths are analyzed. The shorter the heel length, the larger those of inside slip surface, however those of outside slip surface are not changed. According to the relative heel length, relationships of internal friction angle of backfill material - wall friction angle between caisson structure and backfill - friction angle acting on virtual section at the end of heel are presented. Earth pressures acting against caisson structure with relatively short heel are smaller than Rankine earth pressure but always greater than Coulomb earth pressure which does not consider the heel length.

• Biomolecules & Therapeutics
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• v.4 no.2
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• pp.196-201
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• 1996

The N-methyl-D-aspartate (NMDA) receptor-ion channel complex is activated by the simultaneous presence of L-glutamate and glycine, allowing the binding of MK-801 to the phencyclidine (PCP) site of the receptor. The $[^3H]$MK-801 binding assay system was established for determination of pharmacological functions of test compounds acting at the glycine site of the receptor. The binding in the presence of 0.1 $\mu$M L-glutamate was increased by an agonist (glycine) in a dose-dependent fashion, while decreased by either partial agonist (R-(+)-HA-966) or antagonist (5,7-dichlorokynurenic acid: 5,7-DCKA). To distinguish partial agonism from antagonism, various concentrations of 7-chlorokynurenic acid (7-CKA) were added in the assay to eliminate the interference of the endogenous glycine present in the membrane preparations. The bindings in the presence of L-glutamate (0.1$\muM$) and 7-CKA (1, 5, or 10$\muM$) were increased by R-(+)-HA-966. Being a weak partial agonist, the extent of potentiation was much less than that by the agonist. These binding profiles were clearly distinguishable from those by the antagonist, 5,7-DCKA, which exhibited no intrinsic activity. The binding assays established in the present study are a useful system to classify ligands acting at the glycine site of the NMDA receptor by their pharmacological functions.

• The Pure and Applied Mathematics
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• v.15 no.4
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• pp.401-406
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• 2008

Given operators X and Y acting on a separable complex Hilbert space H, an interpolating operator is a bounded operator A such that AX=Y. In this article, we investigate Hilbert-Schmidt interpolation problems for operators in a tridiagonal algebra and we get the following: Let ${\pounds}$ be a subspace lattice acting on a separable complex Hilbert space H and let X=$(x_{ij})$ and Y=$(y_{ij})$ be operators acting on H. Then the following are equivalent: (1) There exists a Hilbert-Schmidt operator $A=(a_{ij})$ in Alg${\pounds}$ such that AX=Y. (2) There is a bounded sequence $\{{\alpha}_n\}$ in $\mathbb{C}$ such that ${\sum}_{n=1}^{\infty}|{\alpha}_n|^2<{\infty}$ and $$y1_i={\alpha}_1x_{1i}+{\alpha}_2x_{2i}$$ $$y2k_i={\alpha}_{4k-1}x_2k_i$$ $$y{2k+1}_i={\alpha}_{4k}x_{2k}_i+{\alpha}_{4k+1}x_{2k+1}_i+{\alpha}_{4k+2}x_{2k+2}_i\;for\;all\;i,\;k\;\mathbb{N}$$.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.171-177
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• 2011

Tsunami forces acting on coastal structures have not been relatively much paid attention by researchers. However, they should be appropriately reflected in design of coastal and harbor facilities. The temporary and permanent tsunami shelters have to be chosen to resist stably against unexpected tsunami forces. There have been only few numerical studies on the tsunami forces acting on coastal and harbor structures. In this study, a practical prediction of tsunami forces is carried out by using a two-dimensional numerical model.

• Journal of Korean society of Dental Hygiene
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• v.18 no.6
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• pp.879-889
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• 2018

Objectives: This study aimed to provide basic data to establish a foundation for efficient operation of the organization by identifying the factors that affect the job embeddedness of dental hygienists. Methods: A survey was conducted from March to July 2018, targeting dental hygienists working in dental clinics and hospitals. Results: The study of the factors affecting job embeddedness of dental hygienists revealed that along with career, marital status, surface acting of emotional labor, and even emotional hiding and false expression, which are sub-areas of the surface acting, have statistically significant influences on job embeddedness. In other words, in a married dental hygienist with relatively high work experience, the surface acting of emotional labor is found to be high in job embeddedness, and the explanatory power of the model is approximately 53.2%. Conclusions: In order to improve the job embeddedness of clinical dental hygienists, it seems necessary to prepare an effective program to strengthen the surface behavior of emotional labor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.4
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• pp.207-214
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• 2022

A prediction model is proposed for a blast load acting on a column component because of an external explosion. The model can predict the pressure-time histories acting on a column using the fitting curves established from a database composed of finite-element (FE) analysis results. To this end, 70 numerical simulations using the commercial software AUTODYN were performed by changing the column width. To confirm the performance of the proposed model, pressure-time histories estimated from an existing empirical formula and the proposed model were compared based on the FE analysis results. It was verified that the proposed model can more precisely predict the pressure-time histories compared with the existing model.

• Geomechanics and Engineering
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• v.34 no.6
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• pp.611-621
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• 2023

This paper presents the results of a numerical investigation of the effect of geotextile reinforcement on underlying buried pipe behavior using PLAXIS 3D. In this study, variable parameters such as the in-plane stiffness of the geotextile, the pipe stiffness, the soil stiffness, the footing width, the geotextile width, and the location of the geotextile reinforcement layer are investigated. Deflections and bending moments acting on the pipe are evaluated for different combinations of variables and are presented graphically. It is observed that with an increase in the in-plane stiffness of the geotextile reinforcement, there is a tendency for a decrease in both deflections in the pipe and bending moments acting on the pipe. Conversely, with an increase in the pipe stiffness, geotextile reinforcement efficiency decreases. In the investigated region of soil stiffness, for the given pipe and geotextile stiffness, an optimum efficiency of geotextile is observed in medium dense soils. Further, it is shown that relative lengths of geotextile and footing has an important role on geotextile efficiency. Lastly, it is also demonstrated that relative location of geotextile layer with respect to the buried pipe plays an important role on the geotextile efficiency in reducing the bending moments acting on the pipe and deflections in the pipe. In general, geotextiles are more efficient in reducing the bending moments as opposed to reducing deflections of the pipe. Numerical validation is done with an experimental study from the literature to observe the applicability of the numerical model used.

• Journal of Ocean Engineering and Technology
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• v.38 no.2
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• pp.53-63
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• 2024

Submerged breakwaters can be installed underneath floating structures to reduce the external wave loads acting on the structure. The objective of this study was to establish an optimization analysis framework to determine the corresponding shape and position of the submerged breakwater that can minimize or maximize the external forces acting on the floating structure. A two-dimensional frequency-domain boundary element method (FD-BEM) based on the linear potential theory was developed to perform the hydrodynamic analysis. A metaheuristic algorithm, the advanced particle swarm optimization, was newly coupled to the FD-BEM to perform the optimization analysis. The optimization analysis process was performed by calling FD-BEM for each generation, performing a numerical analysis of the design variables of each particle, and updating the design variables using the collected results. The results of the optimization analysis showed that the height of the submerged breakwater has a significant effect on the surface piercing body and that there is a specific area and position with an optimal value. In this study, the optimal values of the shape and position of a single submerged breakwater were determined and analyzed so that the external force acting on a surface piercing body was minimum or maximum.

• Journal of the Korean Geosynthetics Society
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• v.14 no.2
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• pp.23-33
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• 2015

The earth pressure acting on underground structure was measured by application of the instrumentation system in the subway construction site constructed by the method of cut-and-cover tunnel. The measured earth pressure was compared with the earth pressure obtained from the existed theoretical equation, and the actual earth pressure diagram acting on the underground structure was investigated. As a result of investigation, the vertical earth pressure is mainly affected by the embankment height, and the lateral earth pressure is significantly affected by whether the existence of earth retaining structures or not. The measured vertical earth pressure is very similar to the theoretical earth pressure proposed by Bierbaumer. The measured lateral earth pressure is closed to the active earth pressure proposed by Rankine rather than the earth pressure at rest. The coefficient of earth pressure in soil deposit layer is about 0.35, and the coefficient in soft rock deposit layer is about 0.21. For design and construction the underground structures, therefore, it is reasonable estimation that the lateral earth pressure acting on structures installed in soil deposit layers is an average value between active earth pressure and earth pressure at rest. In rock deposit layers, the lateral earth pressure acting on structure is an active earth pressure only.