• Title/Summary/Keyword: Large-scale experiments

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Stereo matching for large-scale high-resolution satellite images using new tiling technique

  • Hong, An Nguyen;Woo, Dong-Min
    • Journal of IKEEE
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    • v.17 no.4
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    • pp.517-524
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    • 2013
  • Stereo matching has been grabbing the attention of researchers because it plays an important role in computer vision, remote sensing and photogrammetry. Although most methods perform well with small size images, experiments applying them to large-scale data sets under uncontrolled conditions are still lacking. In this paper, we present an empirical study on stereo matching for large-scale high-resolution satellite images. A new method is studied to solve the problem of huge size and memory requirement when dealing with large-scale high resolution satellite images. Integrating the tiling technique with the well-known dynamic programming and coarse-to-fine pyramid scheme as well as using memory wisely, the suggested method can be utilized for huge stereo satellite images. Analyzing 350 points from an image of size of 8192 x 8192, disparity results attain an acceptable accuracy with RMS error of 0.5459. Taking the trade-off between computational aspect and accuracy, our method gives an efficient stereo matching for huge satellite image files.

A Study on Manufacturing and Experimental Techniques for the 1/5th Scale Model of Precast Concrete Large Panel Structure (프리캐스트 콘크리트 대형판 구조물의 1/5 축소모델 제작 및 실험기법 연구)

  • 김상규;이한선
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.10a
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    • pp.198-203
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    • 1995
  • The objective of this study is to provide the information on the techniques of manufacturing and experiment in small scale modeling of precast concrete(P.C.)large panel structures. The adopted scale was 1/5th 4types of experiments were performed : material tests for model concrete and model reinforcement, compressive test of horizontal joint, shear test of vertical joint and cyclic static test of 2-story subassemblage structure. Based on the experimental results, the following conclusions are drawn: (1)Model concrete may have in general larger compressive strength than expected. (2) Model reinforcement can show less ductility if the annealing processes were performed without using vaccuum tube. (3) Failure modes of horizontal and vertical joints were almost same for both prototype and model. But the strength of model appears to be higher than required by similitude law. (4)Hysteretic behavior of 1/5 scale subassemblage model can be made quite similar to prototype's if the ductility of model reinforcement and compressive strength of model concrete could be representative of those of prototype.

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A Study on Korean Sentiment Analysis Rate Using Neural Network and Ensemble Combination

  • Sim, YuJeong;Moon, Seok-Jae;Lee, Jong-Youg
    • International Journal of Advanced Culture Technology
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    • v.9 no.4
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    • pp.268-273
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    • 2021
  • In this paper, we propose a sentiment analysis model that improves performance on small-scale data. A sentiment analysis model for small-scale data is proposed and verified through experiments. To this end, we propose Bagging-Bi-GRU, which combines Bi-GRU, which learns GRU, which is a variant of LSTM (Long Short-Term Memory) with excellent performance on sequential data, in both directions and the bagging technique, which is one of the ensembles learning methods. In order to verify the performance of the proposed model, it is applied to small-scale data and large-scale data. And by comparing and analyzing it with the existing machine learning algorithm, Bi-GRU, it shows that the performance of the proposed model is improved not only for small data but also for large data.

An Experimental Study of Forming Process Development in Large Nozzle-Shaped Product Using the Incremental Forging Method for Expanding (점진적 팽창단조법에 의한 대형 노즐형제품의 성형공정 개발에 관한 실험적 연구)

  • Park, C.Y.;Yang, D.Y.;Lee, K.H.;Eun, I.S.
    • Transactions of Materials Processing
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    • v.3 no.1
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    • pp.110-119
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    • 1994
  • In this paper, a new forming process of large-size forgings of converged nozzle-shape is developed by the experimental study using the incremental forging method and combined forming method. The development of the forming process is focused on the manufacturing of large-size forgings by the press with medium load capacity. Various related processes are proposed and modelling experiments using plasticine are carried out. Thus, the incremental forging method for expanding is recommanded from the study of formability and forming load, etc. The selected process is then subjected to modelling experiments of lead and the design parameters such as preform for final process, die-width of the upper die and reduction amount of each stroke are determined. In order to verify the effectiveness of the selected process, 1/7 scale prototype experiment of the real material is carried out. Forgings of converged nozzle shape can be produced by the developed process within the limit loads and with the simple tools.

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Towards guidelines for design of loose-laid roof pavers for wind uplift

  • Mooneghi, Maryam Asghari;Irwin, Peter;Chowdhury, Arindam Gan
    • Wind and Structures
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    • v.22 no.2
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    • pp.133-160
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    • 2016
  • Hurricanes are among the most costly natural hazards to impact buildings in coastal regions. Building roofs are designed using the wind load provisions of building codes and standards and, in the case of large buildings, wind tunnel tests. Wind permeable roof claddings like roof pavers are not well dealt with in many existing building codes and standards. The objective of this paper is to develop simple guidance in code format for design of loose-laid roof pavers. Large-scale experiments were performed to investigate the wind loading on concrete roof pavers on the flat roof of a low-rise building in Wall of Wind, a large-scale hurricane testing facility at Florida International University. They included wind blow-off tests and pressure measurements on the top and bottom surfaces of pavers. Based on the experimental results simplified guidelines are developed for design of loose-laid roof pavers against wind uplift. The guidelines are formatted so that use can be made of the existing information in codes and standards such as American Society of Civil Engineering (ASCE) 7-10 standard's pressure coefficients for components and cladding. The effects of the pavers' edge-gap to spacer height ratio and parapet height to building height ratio are included in the guidelines as adjustment factors.

Experimental assessment of thermal radiation effects on containment atmospheres with varying steam content

  • R. Kapulla;S. Paranjape;U. Doll;E. Kirkby;D. Paladino
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4348-4358
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    • 2022
  • The thermal-hydraulics phenomena in a containment during an accident will necessarily include radiative heat transfer (i) within the gas mixture due to the high radiative absorption and emission of steam and (ii) between the gas mixture and the surrounding structures. The analysis of some previous PANDA experiments (PSI, Switzerland) demonstrated the importance of the proper modelling of radiation for the benefit of numerical simulations. These results together with dedicated scoping calculations conducted for the present experiments indicated that the radiative heat transfer is considerable, even for a very low amount of steam (≈2%). The H2P2 series conducted in the large-scale PANDA facility at the Paul-Scherrer-Institut (PSI) in the framework of the OECD/NEA HYMERES-2 project is intended to enhance the understanding of thermal radiation phenomena and to provide a benchmark for corresponding numerical simulations. Thus, the test matrix was tailored around the two opposite extremes: either gas compositions with small steam content such that radiative heat transfer phenomena can be neglected. Or gas mixtures containing larger amounts of steam, so that radiative heat transfer is expected to play a dominant role. The H2P2 series consists of 5 experiments designed to isolate the radiation phenomena from convective and diffusive effects as much as possible. One vessel with a diameter of 4 m and a height of 8 m was preconditioned with different mixtures of air / steam at room and elevated temperatures. This was followed by the build-up of a stable helium stratification at constant pressure in the upper part of the vessel. After that, helium was injected from the top into the vessel which leads to an increase of the vessel pressure and a corresponding elevation-dependent and transient rise of the gas temperature. It is shown that even the addition of small amounts of steam in the initial gas atmosphere considerably impacts the radiative heat transport throughout all phases of the experiments and markedly influences i) the monitored gas peak temperature, ii) the temperature history during the compression and iii) the following relaxation phase after the compression was stopped. These PANDA experiments are the first of its kind conducted in a large scale thermal-hydraulic facility.

A Study on the Pollutant Dispersion over a Mountain Valley Region (II) : Numerical Simulation (산악 계곡지형에서의 오염확산에 관한 연구(II) :수치해석)

  • Shim Woo-Sup;Kim Seogcheol;Yoo Seong-Yeon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.1060-1071
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    • 2005
  • Passive gas dispersions over a 1/1000 scale terrain model at Eiffel type wind tunnel were reproduced by numerical simulation. Large eddy simulation was used to treat the sub-grid scale turbulences. The terrain features were represented by millions of point forces densely distributed over the solid surface using the virtual boundary method. The model simulations agreed very well with the experiments in a consistent fashion for all wind directions. The measured profiles of the wind speeds as well as the tracer gas concentrations were nicely simulated by the CFD model at most locations scattered over the model terrain. With scale factor adjusted and the thermal stratification effects incorporated, the CFD model was expected to provide reliable information on pollutant dispersions over the real complex terrains.

Numerical simulation and experimental study of quasi-periodic large-scale vortex structures in rod bundle lattices

  • Yi Liao;Songyang Ma;Hongguang Xiao;Wenzhen Chen;Kehan Ouyang;Zehua Guo;Lele Song
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.410-418
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    • 2024
  • Study of flow behavior within rod bundles has been an active topic. Surface modification technologies are important parts of the design of the fourth generation reactor, which can increase the strength of the secondary flow within the rod bundle lattices. Quasi-periodic large-scale vortex structure (QLVS) is introduced by arranging micro ribs on the surface of rod bundles, which enhanced the scale of the secondary flow between the rod bundle lattices. Using computational fluid dynamics (CFD) and water experiments, the flow field distribution and drag coefficient of the rod-bundle lattices are studied. The secondary flow between the micro-ribbed rod-bundle lattice is significantly enhanced compared to the standard rod-bundle lattice. The numerical simulation results agree well with the experimental results.

Web Catchphrase Improve System Employing Onomatopoeia and Large-Scale N-gram Corpus

  • Yamane, Hiroaki;Hagiwara, Masafumi
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.12 no.1
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    • pp.94-100
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    • 2012
  • In this paper, we propose a system which improves text catchphrases on the web using onomatopoeia and the Japanese Google N-grams. Onomatopoeia is regarded as a fundamental tool in daily communication for people. The proposed system inserts an onomatopoetic word into plain text catchphrases. Being based on a large catchphrase encyclopedia, the proposed system evaluates each catchphrase's candidates considering the words, structure and usage of onomatopoeia. That is, candidates are selected whether they contain onomatopoeia and they use specific catchphrase grammatical structures. Subjective experiments show that inserted onomatopoeia is effective for making attractive catchphrases.

An Efficient Face Recognition using Feature Filter and Subspace Projection Method

  • Lee, Minkyu;Choi, Jaesung;Lee, Sangyoun
    • Journal of International Society for Simulation Surgery
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    • v.2 no.2
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    • pp.64-66
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    • 2015
  • Purpose : In this paper we proposed cascade feature filter and projection method for rapid human face recognition for the large-scale high-dimensional face database. Materials and Methods : The relevant features are selected from the large feature set using Fast Correlation-Based Filter method. After feature selection, project them into discriminant using Principal Component Analysis or Linear Discriminant Analysis. Their cascade method reduces the time-complexity without significant degradation of the performance. Results : In our experiments, the ORL database and the extended Yale face database b were used for evaluation. On the ORL database, the processing time was approximately 30-times faster than typical approach with recognition rate 94.22% and on the extended Yale face database b, the processing time was approximately 300-times faster than typical approach with recognition rate 98.74 %. Conclusion : The recognition rate and time-complexity of the proposed method is suitable for real-time face recognition system on the large-scale high-dimensional face database.