• Title/Summary/Keyword: Validity issue

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Dynamic Analysis of a Moving Vehicle on Flexible beam Structure (II) : Application

  • Park, Tae-Won;Park, Chan-Jong
    • International Journal of Precision Engineering and Manufacturing
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    • v.3 no.4
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    • pp.64-71
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    • 2002
  • Recently, mechanical systems such as a high-speed vehicles and railway trains moving on flexible beam structures have become a very important issue to consider. Using the general approach proposed in the first part of this paper, it is possible to predict motion of the constrained mechanical system and the elastic structure, with various kinds of foundation supporting conditions. Combined differential-algebraic equation of motion derived from both multibody dynamics theory and finite element method can be analyzed numerically using a generalized coordinate partitioning algorithm. To verify the validity of this approach, results from the simply supported elastic beam subjected to a moving load are compared with the exact solution from a reference. Finally, parametric study is conducted for a moving vehicle model on a simply supported 3-span bridge.

Development of a new free wake model considering a waketower interaction for a horizontal axis wind turbine (후류와 타워의 영향을 고려한 수평축 풍력발전기 블레이드의 비정상 하중 예측을 위한 새로운 자유후류기법의 연구)

  • Shin Hyungki;Park Jiwoong;Lee Soongab;Kim Jueon
    • New & Renewable Energy
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    • v.1 no.1 s.1
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    • pp.54-63
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    • 2005
  • A critical issue in the field of the rotor aerodynamics is the treatment of the wake. The wake is of primary importance in determining overall aerodynamic behavior, especially, a wind turbine blade includes the unsteady airloads problem. In this study, the wake generated by blades are depicted by a free wake model to analyse unsteady loading on blade and a new free wake model named Finite Vortex Element(FVE hereafter) is devised in order to include a wake-tower interaction. In this new free wake model, blade-wake-tower interaction is described by cutting a vortex filament when the filament collides with a tower. This FVE model is compared with a conventional free wake model and verified by a comparison with NRELand SNU wind tunnel model. A comparison with NREL and SNU data shows validity and effectiveness of devised FVE free wake model and an efficient.

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A Taguchi Approach to Parameter Setting in a Genetic Algorithm for General Job Shop Scheduling Problem

  • Sun, Ji Ung
    • Industrial Engineering and Management Systems
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    • v.6 no.2
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    • pp.119-124
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    • 2007
  • The most difficult and time-intensive issue in the successful implementation of genetic algorithms is to find good parameter setting, one of the most popular subjects of current research in genetic algorithms. In this study, we present a new efficient experimental design method for parameter optimization in a genetic algorithm for general job shop scheduling problem using the Taguchi method. Four genetic parameters including the population size, the crossover rate, the mutation rate, and the stopping condition are treated as design factors. For the performance characteristic, makespan is adopted. The number of jobs, the number of operations required to be processed in each job, and the number of machines are considered as noise factors in generating various job shop environments. A robust design experiment with inner and outer orthogonal arrays is conducted by computer simulation, and the optimal parameter setting is presented which consists of a combination of the level of each design factor. The validity of the optimal parameter setting is investigated by comparing its SN ratios with those obtained by an experiment with full factorial designs.

Stroke Width Based Skeletonization for Text Images

  • Nguyen, Minh Hieu;Kim, Soo-Hyung;Yang, Hyung Jeong;Lee, Guee Sang
    • Journal of Computing Science and Engineering
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    • v.8 no.3
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    • pp.149-156
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    • 2014
  • Skeletonization is a morphological operation that transforms an original object into a subset, which is called a 'skeleton'. Skeletonization has been intensively studied for decades and is a challenging issue especially for special target objects. This paper proposes a novel approach to the skeletonization of text images based on stroke width detection. First, the preliminary skeleton is detected by using a Canny edge detector with a Tensor Voting framework. Second, the preliminary skeleton is smoothed, and junction points are connected by interpolation compensation. Experimental results show the validity of the proposed approach.

A study on the korean standard code for information interchange (한국공업규격 한자코드에 대한 고찰)

  • 이춘택
    • Journal of Korean Library and Information Science Society
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    • v.25
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    • pp.295-338
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    • 1996
  • The findings from this study are summarized as follows : 1. It is questionable to define the term "Hanja" as "the Chinese Character used independently or used along with Hangul. 2. It is found to be a problem that the validity and objectivity in the selection of Hanja are lacking. 3. It is also a problem that there is neither principles nor consistency in styling of characters. 4. The system of arrangement has problems, too. The adoption of arrangement of Hanja by its Korean pronunciation results in lots of errors and mistakes. Besides, mistaken strokes and radicals produced considerable errors in the arrangement of Hanja. 5. The omission of the abbreviated Hanja in the Code can be considered to neglect the current trend of increased use of them. 6. The issue concerned with the Japanese-origin Hanja is that several number of Hanja deemed unnecessary are included.y are included.

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Influences of Inter-electrode Distance on Electrogastrography Measurements (위전도 측정을 위한 전극간 부착거리에 관한 연구)

  • Han, Wan-Taek;Song, In-Ho;Kim, In-Young
    • Journal of Biomedical Engineering Research
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    • v.30 no.4
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    • pp.341-346
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    • 2009
  • Cutaneous electrogastrography is the measurement of electrical activity of the stomach on the abdominal surface. The validity of cutaneous electrogastrography is dependent upon the quality of the recording technique. The locations of electrodes are an important issue. We examined the influences of the inter-electrode distance of bipolar leads on electrogastrography measurements. The sensitivity distributions of EGG leads were calculated based on a 2D body fat model and evaluated according to the region of interest sensitivity ratio (ROISR). We simulated the ROISR of the inter-electrode distance in relation to various body fat thicknesses. The distance between the electrodes was proportional to the distance between the ROI and the surface of the abdomen. The results imply that inter-electrode distance can be applied in electrogastrography according to human body fat thickness.

Building a Product Design of Innovative Strategy for Creating Enterprise Development

  • Liao, Shih-Chung
    • The Journal of Industrial Distribution & Business
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    • v.5 no.1
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    • pp.17-25
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    • 2014
  • Purpose - Nowadays, the innovative design concept is being implemented in product design. In order to satisfy market trends and the demand for quality, designers should employ customer satisfaction questionnaires and analyze them with various experimental processes. Research design, data, and methodology - These methodologies would help designers have a better understanding of their customers and judge the market size and clustering validity, by diverse product strategies, for dealing with the rapid change prevailing in the market today. Results - By considering the innovative design with regard to telephones as an experimental case, the study investigates and demonstrates how the product can benefit from market-oriented and customized management concepts, when creative design ability is utilized for developing the product. Conclusions - Along with the benefit of having an innovative product value, the product can stimulate progress inthe development of the enterprise management, which has emerged as the main issue in the area of social and economic development in every developed country.

A Case Study on Simplified Assessment Method for Site Selection of the Waste Treatment Facilities (폐기물처리 시설 입지선정 효율화 방안을 위한 사례연구)

  • 장성호;손영일
    • Journal of environmental and Sanitary engineering
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    • v.15 no.2
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    • pp.85-94
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    • 2000
  • The comparative evaluation is the most effective method for site selection because the selection of waste treatment facility is to determine the optimum site out of limited candidate sites. This study adopted the ordinal scale evaluation, one of methods of comparative evaluation. The ordinal scale evaluation aims to determine the investigating items referring to the character of sites, to determine the importance factors for investigating items, and to determine the optimum site according to the quantitative evaluation. This study has focussed on reflecting the opinion of residents to the maximum extent with a weight on social and economic aspects, considering the state of confrontation against each other between the autonomous government organization and local residents, which is being emerged as a social issue relating to the evaluation rating on each item of site selection of an optimum site. Therefore, rational, and clear validity investigations and proper reduction of both time and expenses in site selection as well through this a study.

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FINITE ELEMENT ANALYSIS FOR DISCONTINUOUS MAPPED HEXA MESH MODEL WITH IMPROVED MOVING LEAST SQUARES SCHEME

  • Tezuka, Akira;Oishi, Chihiro;Asano, Naoki
    • Proceedings of the Korea Society for Simulation Conference
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    • 2001.10a
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    • pp.373-379
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    • 2001
  • There is a big issue to generate 3D hexahedral finite element (FE) model, since a process to divide the whole domain into several simple-shaped sub-domains is required before generating a continuous mesh with mapped mesh generators. In general, it is nearly impossible to set up proper division numbers interactively to keep mesh connectivity between sub-domains on a complicated arbitrary-shaped domain. If mesh continuity between sub-domains is not required in an analysis, this complicated process can be omitted. Element-free Galerkin method (EFGM) can accept discontinuous meshes, which only requires nodal information. However it is difficult to choose a reasonable influenced domain in moving least squares scheme with non-uniformly distributed nodes in discontinuous FE models. A new FE scheme fur discontinuous mesh is proposed in this paper by applying improved EFGM with some modification to derive FE approximated function in discontinuous parts. Its validity is evaluated on linear elastic problems.

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A Sliding Surface Design for Linear Systems with Mismatched Uncertainties based on Linear Matrix Inequality

  • Jang, Seung-Ho;Kim, Sang-Woo
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.561-565
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    • 2005
  • Sliding mode control (SMC) is an effective method of controlling systems with uncertainties which satisfy the so-called matching condition. However, how to effectively handle mismatched uncertainties of systems is still an ongoing research issue in SMC. Several methods have been proposed to design a stable sliding surface even if mismatched uncertainties exist in a system. Especially, it is presented that robustness and efficiency of SMC for linear systems with mismatched uncertainties can be improved by reducing mismatched uncertainties in the reduced-order system. The reduction method needs a new sliding surface with an additional component based on Lyapunov redesign technique. In this paper, a stable sliding surface which contains additional component to reduce the influence of mismatched uncertainties, is introduced. It is designed by using linear matrix inequalities that guarantees the stability of the system. A numerical example demonstrates the validity of the proposed scheme.

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