• Title/Summary/Keyword: Modelling and evaluation

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Errors in Recorded Information and Calibration of a Catchment Modelling System(I) - Analysis of Measurement Errors in Recorded Information - (기록치 오차와 유역모형의 검정(I) - 기록치 내의 측정 오차 분석 -)

  • Kyung Sook Choi;James E. Ball
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.5
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    • pp.110-116
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    • 2003
  • A catchment modelling system is the summation of the numerous hydrologic, hydraulic and other process models necessary to simulate the response of a catchment to a storm event. Differences between the recorded catchment response and that predicted by a catchment modelling system can arise from structural errors within the catchment modelling system, evaluation errors in the control parameters, or measurement errors in the recorded data being used to assess the reliability of the evaluation of the control parameters. Presented herein is an investigation of the potential measurement errors within the recorded information, which was considered to occur from instrument error in the ultra sonic flow monitor. This investigation was undertaken using three available rating curves at the Musgrave Avenue Stormwater System in Centennial Park, Sydney, developed by Abustan (1997), Water Board (1994), and using Manning's equation.

Real-time Oil Spill Dispersion Modelling (실시간 유출유 확산모델링)

  • 정연철
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.5 no.1
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    • pp.9-18
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    • 1999
  • To predict the oil spill dispersion phenomena in the ocean, the oil spill response model, which can be used for strategic purpose on the oil spill site, based on Lagrangian particle-tracking method was formulated and applied to the neighboring area with Pusan port where the oil spill incident occurred when the tanker ship No.1 Youil struck on a small rock near the Namhyungjeto on September 21, 1995. The real-time tidal currents to be required as input data of the oil spill model were obtained by the two-dimensional hydrodynamic model and the tide prediction model. Evaluation of tidal currents using observation data was successful. For wind data, other input data of oil spill model, observed data on the spot were used. To verify the oil spill model, the oil spill modelling results were compared with the field data obtained from the spill site. Compared the modelling results with the observation data, there exist some discrepancies but the general pattern of modelling results was similar to that of field observation. The modelling results on 7 days after spill occurred showed that the 40% of spilled oil is in floating, 36% in evaporated, 23% at shore, and 1% in out of boundary, respectively. According to the evaluation of weighting curves of effective components to the dispersion of oil, the winds make a 37% of contribution to the dispersion of oil, turbulent diffusion 39.5%, and tidal currents 23.5%, respectively. Provided the more accurate wind data are supported, more favorable results might be obtained.

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Trend of Physical Modelling For Ground Subsidence And Study of Its Application (지반함몰 모형실험 연구동향 및 적용방안 고찰)

  • Jeong, Seong-Yun;Jeong, Yeong-Hoon;Kim, Dong Soo
    • Journal of Korean Society of Disaster and Security
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    • v.10 no.1
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    • pp.1-10
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    • 2017
  • Recently, increasing cases of ground subsidence in the urban area has become social issue, and related bill has been passed. Ground subsidence occurs through complex combination of various factors, and numerical analysis of this problem is limited thereby. This is why verification of ground subsidence mechanism has been conducted through physical modelling. Previous researches has been focused on modelling ground subsidence caused by utility pipe defects, and there has been insufficient physical modelling study on ground subsidence caused by various reasons such as groundwater flow and excavation activity. Also, most previous physical modelling studies were performed in 1g condition, which cannot take the in-situ stress condition into the evaluation of the ground subsidence mechanism. Therefore, in this study, physical modelling techniques to simulate various conditions is discussed by studying the previous researches on the ground subsidence mechanism through physical modelling. Also, centrifuge modelling test is suggested in this study as the technique to perform more reliable evaluation of ground subsidence mechanism. Lastly, this study suggests to apply the techniques used in the evaluation of ground subsidence mechanism into Ground Stability Assessment.

Design of a Feature-based Multi-viewpoint Design Automation System

  • Lee, Kwang-Hoon;McMahon, Chris A.;Lee, Kwan-H.
    • International Journal of CAD/CAM
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    • v.3 no.1_2
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    • pp.67-75
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    • 2003
  • Viewpoint-dependent feature-based modelling in computer-aided design is developed for the purposes of supporting engineering design representation and automation. The approach of this paper uses a combination of a multi-level modelling approach. This has two stages of mapping between models, and the multi-level model approach is implemented in three-level architecture. Top of this level is a feature-based description for each viewpoint, comprising a combination of form features and other features such as loads and constraints for analysis. The middle level is an executable representation of the feature model. The bottom of this multi-level modelling is a evaluation of a feature-based CAD model obtained by executable feature representations defined in the middle level. The mappings involved in the system comprise firstly, mapping between the top level feature representations associated with different viewpoints, for example for the geometric simplification and addition of boundary conditions associated with moving from a design model to an analysis model, and secondly mapping between the top level and the middle level representations in which the feature model is transformed into the executable representation. Because an executable representation is used as the intermediate layer, the low level evaluation can be active. The example will be implemented with an analysis model which is evaluated and for which results are output. This multi-level modelling approach will be investigated within the framework aimed for the design automation with a feature-based model.

A Study on method of Using Ultrasonic Transducers With shear wave Polarization Direction (전단파 분극현상을 갖는 초음파 탐촉자 민감도 기법에 관한 연구)

  • 나승우;임광희;송상기;정동화;양인영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.744-747
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    • 2001
  • This paper shows shear wave behavior of CFRP composite laminates as a polar grid form to evaluate vibration pattern of ultrasonic transducers, which gives measured modelling fundamental contents of nondestructive evaluation. Polarized direction can be obtained by using a c-scanner and sensitivity of transducers is founded when using through-transmission method of two transducers. And modelling of vector decomposition is presented based on ply-to-ply method to apply practicable nondestructive evaluation of CFRP laminate lay up. This modelling decomposes the transmission of linearly polarized wave into orthogonal components through each ply of a laminate. It is found that a high provable shows between the model and experimental developed in characterizing layup of CFRP composite laminates.

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A literature review on clinical/ laboratory misfit evaluation on implant-prosthesis (임플란트와 상부보철물의 임상적/실험적 부적합 평가에 관한 문헌고찰)

  • Kim, Jong-Hoi;Cho, Woong-Rae;Ko, Kyung-Ho;Huh, Yoon-Hyuk;Park, Chan-Jin;Cho, Lee-Ra
    • The Journal of the Korean dental association
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    • v.56 no.9
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    • pp.462-478
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    • 2018
  • The presence of implant-prosthesis misfits can cause various complications. It is very important to detect misfits to prevent such complications. There are various evaluation methods for misfit assessment including clinical methods and laboratory in vitro methods. The clinical misfit evaluation includes radiographic analysis, visual observation, probing, Sheffield test, evaluation with disclosing materials, and screw resistance test. The laboratory in vitro evaluation method includes indirect modelling evaluation and direct metrological visualization. Of the indirect modelling methods, photoelastic stress analysis, finite element analysis, strain gauge analysis, and microbial colonization analysis were reviewed. Of the direct metrological visualization, microscopic analysis, 3-D photogrammetric analysis, coordinate measuring analysis, and radiographic analysis were reviewed. In this review, the characteristics, advantages and disadvantages of each method were evaluated.

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Centrifuge Modelling of Bridge Abutment Foundation on the Sloped Ground (경사지반에 위치한 교대기초의 원심모델링)

  • Yoo, Nam-Jae;Jun, Sang-Hyun;Hong, Young-Kil
    • Journal of Industrial Technology
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    • v.27 no.B
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    • pp.209-214
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    • 2007
  • This paper is the research result about centrifuge model experiments of investigating the behavior of bridge abutment on the sloped ground. Ground condition of the studied site was the bridge abutment with pile foundation adjacent to the slope. The pile foundations was supported on the soft rocks covered with the embankment. Evaluating the behavior of such a complicate ground and structure conditions was not easy so that the centrifuge modelling was performed to find the overall behavior of them. Layout of centrifuge model experiment was simplified to simulate easily the actual behavior of very complicate site condition. Construction process in field such as ground excavation for footing foundation, installation of piles, placement of footing and bridge abutment, backfilling and surcharge loading eas duplicated in the centrifuge model experiment. Consequently, the stability of the piled bridge abutment adjacent to the slope of embankment was evaluated throughout centrifuge modelling.

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- A 3D Evaluation System on Web for Reliable Furniture Product Development - (신뢰성 높은 가구산업 신제품의 3D Modeling Solution 개발에 관한 연구)

  • Jin Han Xin;Paik Byung Chul;Lee Chang Ho
    • Journal of the Korea Safety Management & Science
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    • v.6 no.4
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    • pp.227-238
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    • 2004
  • This development has tried to scheme out the convenience for users to use the 3D modeling solution which is developed from the existing programs. The extended 3D modeling solution, to be developed through the use of the API which is provided and Microsoft Access, database is able to reuse the parts, subassemblies of parts, and assemblies. A methodology exhibits the possibility to use a Spinfire Professional Spinfire Reader program. The web evaluation system, which is used to connected with the Internet explorer and to construct a web service, will repeat the evaluations of the company staffs and customers about the new products which the company have designed. The furniture manufacturing company will adopt the 3D modelling solution in modelling the new products and go through the web evaluation system to collect dissatisfied facts of the customers or the company staffs against the new product. Finally, it will contribute to the enormous benefit creation of the enterprise.

Structural Performance Evaluation of Stone Pagoda of Mireuk Temple Site in accordance with Construction Type (미륵사지 석탑의 축조형식에 따른 구조성능 평가)

  • Kim, Ho-Soo;Park, Chan-Hong;Lee, Ha-Na
    • Journal of Korean Association for Spatial Structures
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    • v.14 no.2
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    • pp.41-50
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    • 2014
  • The stone pagoda of Mireuk temple site is currently restoring through the repairing process. This stone pagoda has the various construction types in the inner and outer space. Therefore, the stress concentration and structural behavior need to be considered through the analysis of various construction patterns. To this end, this study presents the structural modelling and analysis considering the discrete element analysis technique to solve the discontinuum behavior between the stone elements. Also, this study performs the structural performance evaluation through the various design variables for the safety of stone pagoda. Through the analysis results, we can find out the small stress concentration in the several members. But, because the stresses and displacements are relatively small, we can secure the safety of the whole structure.

- A Component-Based Manufacturing Information Systems for DFM Using UML - (UML을 이용한 컴포넌트 기반의 DFM을 위한 제조정보 시스템의 개발)

  • 김진대;이홍희
    • Journal of the Korea Safety Management & Science
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    • v.5 no.2
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    • pp.75-85
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    • 2003
  • Manufacturing firms have adapted seriously the Design for Manufacture and Assembly (DFMA) techniques which consider concurrently all factors related to the product development by using effective communications and sharing of information on product development processes. This study performed modelling and characterizing the data related to product manufacturing information for Design for Manufacture(DFM) evaluation and analysis. It adapted component-based development method for communicating and managing manufacturing information among distributed manufacturing organizations. Introducing component-based development offers safety and speed to network based system. This development using Unified Modelling Language(UML) provides efficient way for reconstruction and distribution of applications. Also, the integration of database and component into the internet environment enables to communicate and manage effectively manufacturing information for DFM evaluation and analysis at any place in the world. Therefore this system can make it more reasonable that evaluating, analyzing, and effective decision making of product design using DFM technique.