• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.109-118
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• 2007

The excavation damaged zone (EDZ) is an area around an excavation where in situ rock mass properties, stress condition. displacement. groundwater flow conditions have been altered due to the excavation. Various studies have been carried out on EDZ, but most studies have been focused on the mechanical bahavior of EDZ by in situ experiment. Even though the EDZ could potentially form a high permeable pathway of groundwater flow, only a few studies were performed on the analysis of groundwater flow in EDZ. In this study, the' hydraulic EDZ' was defined as the rock Lone adjacent to the excavation where the hydraulic aperture has been changed due to the excavation. And hydraulic EDZ (hydraulic aperture changed zone) estimated by two-dimensional DEM program was considered in three-dimensional DFN model. From this approach the groundwater flow characteristics corresponding to hydraulic aperture change were examined. Together. a parametric study was performed to examine the boundary conditions that frequently used in DFN analysis such as constant head or constant flux condition. According to the numerical analysis, hydraulic aperture change induced by the hydraulic-mechanical interaction becomes one of the most important factors Influencing the hydraulic behavior of jointed rock masses. And also from this study, we suggest the proper boundary condition in three-dimensional DFN model.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.99-103
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• 2010

A new analytic solution was derived for the diffusion into or from an immobile zone of a rectangular 2-D pore. For a long time, the new solution converges to a traditional mobile-immobile zone (MIM) model, but only if the latter is used with an apparent initial concentration that is smaller by almost 20% than the true one. This is the tradeoff for using a simple MIM model instead of an exact model based on the diffusion equation. The mass-transfer coefficient was found to be constant for a sufficiently long time; it was proportional to the molecular diffusion and inversely proportional to the square of the pore depth. The mass-transfer coefficient was time-dependent for a sufficiently short time and may be significantly larger than its asymptotic value.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.11
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• pp.973-980
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• 2016

An air traffic management (ATM) has been studied in a variety of fields to utilize an air traffic capacity efficiently and solve a congested air traffic situation due to an increment of an air traffic demand. In this paper, an air traffic management, which is related with controlling and determining the sequencing of an aircraft approaching to an airport, in terminal control area is studied. This paper focuses on scheduling algorithms with a given problem for the air traffic management with operational constraints, such as a space separation, an overtaking on the same air-route, and a route merge point (a scheduling point). For a real-time calculation, the presented algorithms focus on dispatching heuristic rules which are able to assign tasks in a fast time period with an adequate performance, which can be demonstrated as a proper and realistic scheduling algorithm. A simulation result is presented to illustrate the validity and applicability of the proposed algorithm. Each scheduling rule is analyzed on the same static and dynamic air traffic flow scenario with the ATM Monte-Carlo simulation.

• Proceedings of the Korea Technology Innovation Society Conference
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• 1998.05a
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• pp.23-23
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• 1998

1980년대 이후 계속된 디지털 기술의 발전과 영상처리 기술의 발전은 전통적으로 엄격히 분리 운영되어 온 통신과 방송의 융합화를 촉진하고 있으며, 기존의 미디어 질서를 근본적으로 변화시키고 있다. 이미 통신망과 방송망이 융합하여 하나의 망을 통해 방송서비스와 통신서비스를 동시 제공하는 것이 가능해지고 있으며, VOD, 인터넷방송, FM 방송전파를 통한 무선호출서비스 등 새로운 서비스가 등장하고 있다. 사업자측면에서는 통신사업자와 방송사업자가 상대영역에 진입하거나 M&A를 통해 양 분야의 서비스를 동시에 제공하는 사례가 증가되고 있다. 이에 따라 미국, 영국, 일본 등 선진국뿐만 아니라 EU 차원에서도 최근의 기술발전 추세와 산업계의 동향을 반영하여 통신사업자와 방송사업자간 상호진입 허용, 규제기구의 통합 등 기존의 규제제도를 전면적으로 재검토하고 있다. 미국의 1996년 통신법 개정, EU의 대체인프라스트럭쳐 자유화정책, 영국과 일본에서의 CATV망을 통한 통신서비스제공 허용 등이 그 대표적인 사례이다. 그러나 이러한 세계적인 흐름과 비교하여 볼 때 우리나라의 법/제도 정비 및 정책적 대응은 매우 미진한 상태이다. 현행법은 아직까지 통신망과 방송망간 융합, 사업자간 융합을 엄격히 규제하고 있으며, 서비스의 규제방식 등 통신·방송 융합시대에 대비한 규제제도 정비가 아직까지 미흡한 실정이다. 본 고에서는 통신·방송 융합의 배경과 전개과정, 국내외 융합추진 현황을 살펴보고, 통신·방송 융합 현상에 따른 규제제도상의 과제를 제시하고자 하였다.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.85-93
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• 2008

For music score recognition, several approaches have been proposed including shape matching, statistical methods, neural network based methods and structural methods. In this paper, we deal with recognition for low resolution images which are captured by the digital camera of a mobile phone. Considerable distortions are included in these low resolution images, so when existing technology is used, many problems appear. First, captured images are not stable in the sense that they contain lots of distortions or non-uniform illumination changes. Therefore, notes or symbols in the music score are damaged and recognition process gets difficult. This paper presents recognition technology to overcome these problems. First, musical note to head, stick, tail part are separated. Then template matching on head part of musical note, and remainder part is applied. Experimental results show nearly 100% recognition rate for music scores with single musical notes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.1
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• pp.108-114
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• 2008

Since flash memory cannot be overwritten, new data are updated in new area. If data are frequently updated, garbage collection which is achieved by erasing blocks, should be performed to reclaim new area. Hence, because the count of erase operations is limited due to characteristics of flash memory, every block should be evenly written and erased. However, if data with access locality are processed by cost benefit algorithm with separation of hot block ad cold block though the performance of processing is hight wear-leveling is not even. In this paper, we propose CB-MB (Cost Benefit between Multi Bank) algorithm in which hot data are allocated in one bank and cold data in another bank, and in which role of hot bank and cold bank is exchanged every period. CB-MB shows that its performance is 30% better than cost benefit algorithm with separation of cold block and hot block its wear-leveling is about a third of that in standard deviation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.373-381
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• 2016

In this study, we investigate the characteristics of the drag reduction of a circular cylinder having a detached splitter plate at the wake side. We measure the fluid force on a circular cylinder and visualize the field using particle image velocimetry (PIV) with a high Reynolds number, Re = 10,000. The experimental paraeters used were the width ratios (H/B = 0.5~1.5) of splitters to the prism width and the gap ratios (G/B = 0~2) between the prism and the splitter plate. The drag-reduction rate of the circular cylinder increased with H/B in the case of the same G/B, and it increased and then decreased with G/B in the case of the same H/B. The vortices of the opposite direction on the upper and lower sides of the detached splitter plate were generated by installing the plate. Reverse flow was caused by the vortices at the wake region of the circular cylinder, and the drag of the circular cylinder was decreased by the reverse flow.

• Journal of the Korea Computer Graphics Society
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• v.20 no.4
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• pp.9-16
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• 2014

This paper proposes a novel method that couples fluid and deformation/fracture. Our method considers two interaction types: fluid-object interaction and fluid-fluid interaction. In fluid-fluid interaction, we simulate water and smoke separately and blend their velocities in the intersecting region depend on their densities. Our method separates projection process into two steps for each of water and smoke. This reduces the number of grid cells required for projection in order to optimize the number of iterations for convergence and improve stability of the simulation. In water projection step, smoke region regarded as the cells with Dirichlet boundary condition. The smoke projection step solves water region with Neumann boundary condition. To take care of fluid-object interaction, we make use of the fluid pressure to update velocities of the each of the mass points so that the object can deform or fracture. Although our method doesn't provide physically accurate results, the various examples show that our method generate appealing visuals with good performance.

• Journal of Korean Home Economics Education Association
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• v.16 no.4 s.34
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• pp.1-8
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• 2004

The purpose of this study was to investigate as to how much of changes has occurred in the newly revised Home Economics Textbooks required by the 7th Curriculum as compared to those by the former 6th Curriculum. and to seek future policy direction which can be improved even better. if any. for further revision. To implement this proposal, this study employed 8 different textbooks published among 12 textbooks developed for the 7th Curriculum for data base. The results of this study were as follows: It was covered such areas of change and develope in the composition of category and system in the Home Economics Textbooks required by the 7th Curriculum as compared to those by the former 6th Curriculum. The whole system of textbook was composed of cover page, the inside of a book cover. the title page, introduction. table of contents. appendices. It was same in the total pages with the exception of table of contents. appendices. the inside of a book cover and it was much alike in contents of introduction. In the aspect of the unit system of the textbooks. their whole flows were similar to each other. but the writers' intention and the stress on the focal points had appeared well in topic introduction and texts for the units of the textbooks. In addition. it can be said desirable that much more middle school teachers took a participation in the development of textbooks as textbook writers than before. In the organizational aspect of the sub-area organization of textbooks in the 7th Curriculum, it was not dispersed in grade 1, 2, and 3, but was centralized in a certain grade to increase its efficiency. The number of activity and experiment & practice that students could try to do actually were drastically increased compared to the 6th Curriculum. but it showed a wide difference between textbooks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5A
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• pp.841-848
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• 2006

There is a complex variation of stress in PSC anchorage zones and box girder diaphragms because of large concentrated load by prestress. According to the AASHTO LFRD design code, three-dimensional effects due to concentrated jacking loads shall be investigated using three-dimensional analysis procedures or may be approximated by considering separate submodels for two or more planes. In this case, the interaction of the submodels should be considered, and the model loads and results should be consistent. However, box girder diaphragms are 3-dimensional disturbed region which requires a fully three-dimensional model, and two-dimensional models are not satisfactory to model the flow of forces in diaphragms. In this study, the strengths of the prestressed box girder diaphragms are predicted using the 3-dimensional grid strut-tie model approach, which were tested to failure in University of Texas. According to the analysis results, the 3-dimensional strut-tie model approach can be possibly applied to the analysis and design of PSC box girder anchorage zones as a reasonable computer-aided approach with satisfied accuracy.