• Geomechanics and Engineering
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• 제11권1호
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• pp.117-139
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• 2016

Previous studies for soil movements induced by tunneling have primarily focused on the free soil displacements. However, the stiffness of existing structures is expected to alter tunneling-induced ground movements, the sheltering influences for underground structures should be included. Furthermore, minimal attention has been given to the settings for the shield machine's operation parameters during the process of tunnels crossing above and below existing tunnels. Based on the Shanghai railway project, the soil movements induced by an earth pressure balance (EPB) shield considering the sheltering effects of existing tunnels are presented by the simplified theoretical method, the three-dimensional finite element (3D FE) simulation method, and the in-situ monitoring method. The deformation prediction of existing tunnels during complex traversing process is also presented. In addition, the deformation controlling safety measurements are carried out simultaneously to obtain the settings for the shield propulsion parameters, including earth pressure for cutting open, synchronized grouting, propulsion speed, and cutter head torque. It appears that the sheltering effects of underground structures have a great influence on ground movements caused by tunneling. The error obtained by the previous simplified methods based on the free soil displacements cannot be dismissed when encountering many existing structures.

• Structural Engineering and Mechanics
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• 제84권3호
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• pp.323-335
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• 2022

The main idea of the framework is to seamlessly combine a reasonably accurate and fast surrogate model with the importance sampling strategy. Developing a surrogate model for predicting structures' dynamic responses is challenging because it involves high-dimensional inputs and outputs. For this purpose, a novel surrogate model based on cutting-edge deep learning architectures specialized for capturing temporal relationships within time-series data, namely Long-Short term memory layer and Transformer layer, is designed. After being properly trained, the surrogate model could be utilized in place of the finite element method to evaluate structures' responses without requiring any specialized software. On the other hand, the importance sampling is adopted to reduce the number of calculations required when computing the failure probability by drawing more relevant samples near critical areas. Thanks to the portability of the trained surrogate model, one can integrate the latter with the Importance sampling in a straightforward fashion, forming an efficient framework called TTIS, which represents double advantages: less number of calculations is needed, and the computational time of each calculation is significantly reduced. The proposed approach's applicability and efficiency are demonstrated through three examples with increasing complexity, involving a 1D beam, a 2D frame, and a 3D building structure. The results show that compared to the conventional Monte Carlo simulation, the proposed method can provide highly similar reliability results with a reduction of up to four orders of magnitudes in time complexity.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권4호
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• pp.161-167
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• 2014

Purpose: The reconstruction of mandibular defects poses many difficulties due to the unique, complex shape of the mandible and the temporomandibular joints. With development of microvascular anastomosis, free tissue transplantation techniques, such as deep circumflex iliac artery (DCIA) flap and fibular free flap (FFF), were developed. The DCIA offers good quality and quantity of bone tissue for mandibular segmental defect and implant for dental rehabilitation. Virtual surgical planning (VSP) and stereolithography-guided osteotomy are currently successfully applied in three-dimensional mandibular reconstruction, but most use FFF. There are only a few articles on reconstruction with the DCIA that assess the postoperative results. Methods: Three patients admitted during a five month period (April of 2013 to August of 2013) underwent resection of mandible and DCIA musculo-osseous reconstruction using a VSP and stereolithographic modeling and assessment of outcomes included technical accuracy, esthetic contour, and functional outcomes. Results: This technique yielded iliac bone segment with excellent apposition and duplication of the preoperative plan. Flap survival was 100 percent and all patients maintained preoperative occlusion and contour. Conclusion: Based on our experience, we offer considerations and logically consistent protocols by classification of mandibular defects, and demonstrate the benefits in VSP and stereolithographic modeling of mandibular reconstructive surgery with DCIA flap.

• 패션비즈니스
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• 제14권4호
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• pp.91-101
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• 2010

This paper has the purpose of suggesting a development-method on the fashion products that would secure the competitiveness in the global markets through creating supersensitive practical products on the basis of developing originative fashion-goods being made of jacquard that is fine quality of couture. This paper has collected data through the cases of the developed nations in fashion, precedent studies and all the related literature on the subject. The results of this researching are as following: The first, it is expected that the necessity of developing new fashion products would be appealed toward the prestige group of consumers who are seeking for the fine quality and super-sensitivity in female fashion in Korea, and it is the current situation that the products made of jacquard are gradually expanding not only in the area of apparel, fashion goods and interior but also another areas. The current situation of the global market suggests the necessary strategy of survival, that is, the development of supersensitive materials and creative products which would be able to keep the high quality and lower the selling price through cost reduction. The second, the suggestion of the direction in developing the products of the female fashion made of jacquard has two points - the development of the texture that would realize a unique form and the development of the material that would be able to realize planar pattern and three dimensional pattern which are woven with thin and light materials with various solidity and delicacy through various techniques of mixing and three dimensional expression. The third, the expected ripple effect and utilization generated from the development of fashion products are as followings: As material characteristics of jacquard, It needs the specialization of various techniques and specialized production system in using jacquard, and the specialized technique and system would make it possible to produce not only the higher value-added products through expressing affluent colors and delicate design but also competitive products through cutting the process and cost, eventually, it would lead to the expansion of the jacquard market of super-sensitive prestige. Therefore, it is remarkable that various development of products toward the global market and the prestige female fashion market can suggest the vision that make the national fashion industry develop into the higher value-added knowledge industry integrating technology and culture.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.149-158
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• 1998

Biomass of non-living brown seaweed Sargassun fluitans pretreated with NaOH is capable of taking up more than $10\%$ $(q_{max}$ : 3.85 mmol/g for Al and 1.48 mmol/g for Cu) of its dry weight in the Al and Cu at pH of 4.5. However, the maximum Al and Cu uptakes calculated from Langmuir isotherm were 1.58 mmol/g for Al and 1.35 mmol/g for Cu at pH 3.5. Equilibrium batch sorption study was performed using two-metal system containing Al and Cu. The mathematical model of the two-metal sorption system enabled quantitative estimation of one-metal biosorption inhibition due to the influence of a second metal. NaOH-treated S. fluitans contained 2.19 mmol $(43\;wt.\%)$ carboxyl groups per gram of biomass. A modified form of Langmuir, which assumes binding of Cu as $Cu^{2+}$ and Al as $Al(OH)_2^+,$ was used to model the experimental data. This result agrees with the one of mono-valent sorption for Al in single-metal system. The modified Langmuir model gives the following affinity correlated coefficients: 0.196 for Cu and 6.820 for Ah at pH 4.5, and 2.904 for Cu and 3.131 for Al at pH 3.5. The interference of Al in Cu biosorptive uptake was assessed by `cutting' the three dimensional uptake isotherm surfaces at constant second-metal final concentrations. Equimolar final equilibrium concentrations of Cu and Al of 1 mM at pH 4.5 give Cu and hi uptakes reduced by $82.5\%\;and\;5.4\%,$ respectively. However, these values at pH 3.5 were $55\%\;(Cu)\;and\;31\%$ (Al).

• 한국전산유체공학회지
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• 제13권4호
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• pp.1-7
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• 2008

In the process of continuous hot-dip galvanizing, it is well known that the gas wiping through an air knife system is most effective because of its uniformity in coating thickness, possibility of thin coating, workability in high speed, and simplicity of control. However, gas wiping used in the galvanizing process brings about a problem of splashing at the strip edge above a certain high speed of process. It is also known that the problem of edge splashing is more harmful than that at the mid strip surface. For a given liquid(of a certain viscosity and surface tension), the onset of splashing mainly depends upon the strip velocity, the gas-jet pressure, and the nozzle's stand-off distance. In these connections in the present study, we proposed three kinds of air knife system having nozzles of constant expansion rate, and compared the jet structures issuing from newly proposed nozzle systems with the result by a conventional one. In numerical analysis, the governing equations are consisted of two-dimensional time dependent Navier-Stokes equations, and the standard k-${\varepsilon}$ turbulence model is employed to solve turbulence stress and so on. As the result, it is found that we had better use the constant expansion-rate nozzle which can be interpreted from the point view of the energy saving for the same coating thickness. Also, we better reduce the size of separation bubble and enhance the cutting ability at the strip surface, by using an air-knife having constant expansion-rate nozzle.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.743-748
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• 2005

In order to realize a three-dimensional shape on CAD, the machining process has been widely used because it offers practical advantages such as precision and versatility. However, the traditional machining process needs a large amount of time in cutting a product and the remained material causes trouble such as inconvenience for clarity. Therefore, a new rapid manufacturing process using the hot tool, Rapid Heat Ablation process (RHA), has been developed. In this paper, the hot tool for RHA process is devised to minimize radius of heat affected zone and also investigated for verification. TRIZ well-known as creative problem solving method is applied to overcome the contradictive requirements of the hot tool. For the detailed design of the hot tool, numerical model is established with several assumptions. Based on the numerical results, surface temperature is measured with K-type thermocouple at the predetermined location. Numerical and experimental results show that the devised hot tool fulfils its requirements. It verifies the practicality of hot tool that the hemisphere shape is ablated using the hot tool with stair structure.

• Spatial Information Research
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• 제16권4호
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• pp.479-488
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• 2008

본 논문은 건물추출 기법에 있어서 기존 연구들을 분석하기 위하여 활용센서의 관점에서 분류하고 이에 따라 주요 기법들을 분석하였다. 지난 수십 년간, 많은 유형의 센서자료가 매핑과학기술분야에 도입되어 왔고, 그들의 특성은 공간해상력과 자료처리 측면에서 매우 다양하다. 이에 따라, GIS분야에서 이러한 자료들을 이용함으로써 실세계의 3차원 가상공간 구축이 가능해지고 있고, 이는 도시설계, 재난관리 및 토목공사 등 여러 응용분야에 활용될 수 있을 것으로 기대된다. 이와 관련하여, 본 연구는 건물추출에 대한 기존 연구들을 먼저 건물 영역탐지와 모델링의 두 가지 대주제로 분류한 후 기법들에 대한 장단점을 분석하였다. 본 연구에서 제시하는 분석결과는 목적에 따라 자동화 알고리즘을 향상시키거나 적합한 센서자료를 선택하는데 있어서 유용하게 활용될 수 있을 것이다.

• 대한치과보철학회지
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• 제41권1호
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• pp.20-34
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• 2003

Novel methods producing supplementary and prosthetic material by cutting or discharge processing via computer design have been proposed as alternatives for traditional casting methods and are being utilized for commercial purposes. The CAD/CAM system used in dentistry can be classified into three-dimensional input of target values, restoration design, and material processing. The marginal fidelity in production of In-Ceram core has important clinical implications and is a key consideration issue in CAD/CAM production as well. Through this research, the author arrived at the following conclusion aaer conducting comparison analysis of marginal fidelities between the In-Ceram core produced via CAD/CAM and that produced through the traditional method ; 1. In the cases of mesial, distal, and lingual margins, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 2. In the case of labial flange, the core margins via CAD/CAM produced lower values than those via the traditional method and the differences were found to be statistically significant. (p<0.05) 3. In comparision with overall marginal fidelity, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 4. Among the core margins produced via the traditional method did not have statistically significant differences but fir those produced via CAD/CAM had statistically significant differences between labial and lingual sides and between labial and mesial sides. (p <0.05).

• 대기
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• 제24권1호
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• pp.17-27
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• 2014

In this study, the observational environment for sunshine duration at Seoul and Daegu Automated Synoptic Observing Systems (ASOSs) was analyzed using a numerical model. In order to analyze the effects of topography and buildings on observational environment for sunshine duration, the model domains including the elevated building and mountainous areas around Seoul and Daegu ASOSs were considered. Three dimensional topography and buildings used as input data for the numerical model were constructed using a geographic information system (GIS) data. Solar azimuth and altitude angles calculated for the analysis period (one-week for each season in 2008) in this study were validated against those by Korea Astronomy and Space Science Institute (KASI). The starting and ending times of sunshine duration observed at ASOSs largely differed from the respective sunrise and sunset times simply calculated using solar angles and information of ASOSs' latitude and longitude, because uneven topography and elevated buildings around ASOSs cut off sunshine duration right after the sunrise and right before the sunset. The model produced the sunshine indices for Seoul and Daegu ASOSs with the time interval of one minute and the period of one week for each season and we compared the hourly averaged indices with those observed at the ASOSs. One week of which the cloudiness is lowest for each season is selected for analysis. Not only the adjacent buildings but also distant buildings and mountain cut off sunshine duration right after the sunrise and right before the sunset. The buildings and topography cutting off sunshine duration were found for each analyzing date. It was suggested that, in order to evaluate the observational environment for sunshine duration, we need to consider even the information of topography and/or building far away from ASOSs. This study also showed that the analyzing method considering the GIS data is very useful for evaluation of observational environment for sunshine duration.