• Title, Summary, Keyword: parametric analysis

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Study on Numerical Sensitivity and Uncertainty in the Analysis of Parametric Roll (파라메트릭 횡동요 수치해석의 민감도 및 불확실성에 대한 연구)

  • Park, Dong-Min;Kim, Tae-Young;Kim, Yong-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.1
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    • pp.60-67
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    • 2012
  • This study considers the numerical analysis on parametric roll for container ships. As a method of numerical simulation, an impulse-response-function approach is applied in time domain. A systematic study is carried out for the parametric roll of two container ships, particularly observing the sensitivity of computational results to some parameters which can affect the analysis of parametric roll. The parameters to be considered are metacentric height (GM), simulation time window, and the discretization of wave spectrum. Based on the result of parametric roll simulation, numerical sensitivity and uncertainty in computational analysis are discussed.

Development of a Parametric Design System for Membrane Structures (연성 막구조의 파라메트릭 설계 시스템 개발)

  • Choi, Hyun-chul;Lee, Si Eun;Kim, Chee Kyeong
    • Journal of the Korean Association for Spatial Structures
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    • v.16 no.4
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    • pp.29-36
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    • 2016
  • The objective of this research is to development of a parametric design system for membrane structures. The parametric design platform for the spatial structures has been designed and implemented. Rhino3D is used as a 3D graphic kernel and Grasshopper is introduced as a parametric modeling engine. Modeling components such as structural members, loading conditions, and support conditions are developed for structural modeling of the spatial structures. The interface module with commercial structural analysis programs is implemented. An iterative generation algorithm for design alternatives is a part of the design platform. This paper also proposes a design approach for the parametric design of Spoke Wheel membrane structures. A parametric modeling component is designed and implemented. SOFiSTik is examined to interact with the design platform as the structural analysis module. The application of the developed interface is to design optimally Spoke Wheel Shaped Ductile Membrane Structure using parametric design. It is possible to obtain objective shape by controlling the parameter using a parametric modeling designed for shape finding of spoke wheel shaped ductile membrane structure. Recently, looking at the present Construction Trends, It has increased the demand of the large spatial structure. But, It requires a lot of time for Modeling design and the Structural analysis. Finally an optimization process for membrane structures is proposed.

Bayesian Semi-Parametric Regression for Quantile Residual Lifetime

  • Park, Taeyoung;Bae, Wonho
    • Communications for Statistical Applications and Methods
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    • v.21 no.4
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    • pp.285-296
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    • 2014
  • The quantile residual life function has been effectively used to interpret results from the analysis of the proportional hazards model for censored survival data; however, the quantile residual life function is not always estimable with currently available semi-parametric regression methods in the presence of heavy censoring. A parametric regression approach may circumvent the difficulty of heavy censoring, but parametric assumptions on a baseline hazard function can cause a potential bias. This article proposes a Bayesian semi-parametric regression approach for inference on an unknown baseline hazard function while adjusting for available covariates. We consider a model-based approach but the proposed method does not suffer from strong parametric assumptions, enjoying a closed-form specification of the parametric regression approach without sacrificing the flexibility of the semi-parametric regression approach. The proposed method is applied to simulated data and heavily censored survival data to estimate various quantile residual lifetimes and adjust for important prognostic factors.

Spectral analysis of random process

  • Akizuki, Kageo
    • 제어로봇시스템학회:학술대회논문집
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    • pp.13-20
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    • 1994
  • The spectrum estimation methods of random processes are expressed in this paper. Beginning with the basic theory, non-parametric and parametric methods are overviewed. As to non-parametric method, numerical calculation method is also discussed. As to parametric method, AR model is a very famous and effective model representing random process. Estimation methods of AR parameters which have been proposed are mentioned here. Wavelet analysis is a recently interested technique in signal processing. An application of wavelet analysis is also shown.

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Linearized Methods for Quantitative Analysis and Parametric Mapping of Brain PET (뇌 PET 영상 정량화 및 파라메터영상 구성을 위한 선형분석기법)

  • Kim, Su-Jin;Lee, Jae-Sung
    • Nuclear Medicine and Molecular Imaging
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    • v.41 no.2
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    • pp.78-84
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    • 2007
  • Quantitative analysis of dynamic brain PET data using a tracer kinetic modeling has played important roles in the investigation of functional and molecular basis of various brain diseases. Parametric imaging of the kinetic parameters (voxel-wise representation of the estimated parameters) has several advantages over the conventional approaches using region of interest (ROI). Therefore, several strategies have been suggested to generate the parametric images with a minimal bias and variability in the parameter estimation. In this paper, we will review the several approaches for parametric imaging with linearized methods which include graphical analysis and mulilinear regression analysis.

Energy Analysis of System Constraints using SysML Parametric Diagram (SysML Parametric 다이어그램을 이용한 시스템 제약사항의 소모전력 분석)

  • Lee, Jae-Wuk;Hong, Jang-Eui
    • Journal of Convergence Society for SMB
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    • v.2 no.2
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    • pp.13-19
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    • 2012
  • Various quality requirements have increased in developing embedded systems. One of those requirements in mobile embedded system is to reduce energy consumption because of limited power supply. Especially as the complexity of embedded software is increased, the interests of the software energy consumption analysis is also increased. In recent years, some studies has been carried out model-based analysis because it can be able to reflect energy consumption requirements in design phase. In this paper, we proposes a model-based energy analysis technique using SysML parametric diagram. The proposed technique designs software activity model using characteristics of parametric diagram, and then energy consumption value by the execution of the model is derived. Our technique has merit that can perform tradeoffs analysis for energy quality property between different implementations.

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PARAMETRIC GENERALIZED MIXED IMPLICIT QUASI-VARIATIONAL INCLUSIONS

  • Park, Jong-Yeoul;Jeong, Jae-Ug
    • Journal of the Korean Mathematical Society
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    • v.44 no.4
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    • pp.889-902
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    • 2007
  • An existence theorem for a new class of parametric generalized mixed implicit quasi-variational inclusion problems is established in Hilbert spaces. Further, we study the behavior and sensitivity analysis of the solution set in this class of parametric variational inclusion problems.

An analysis on the Parametric Transformer (Parametric Transformer의 동작해석)

  • Hwang, Young-Moon;Jeong, Kee-Hwa;Park, Han-Woong
    • Proceedings of the KIEE Conference
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    • pp.31-33
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    • 1991
  • A passive power converter operating on the principle of parametric excitation, called Parametric transformer, is analyzed. The energy transfer from the input to the output is achieved through the double frequency variation of magnetic path reluctance to the input frequency without mutual flux coupling between two windings. Thus, output becomes available which is essentially independant of waveform of excitation. The mathmatical model of the device is developed and its solution is obtained. The outstanding characteristics of the device is explained from the analysis.

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Multi-level approach for parametric roll analysis

  • Kim, Tae-Young;Kim, Yong-Hwan
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.3 no.1
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    • pp.53-64
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    • 2011
  • The present study considers multi-level approach for the analysis of parametric roll phenomena. Three kinds of computation method, GM variation, impulse response function (IRF), and Rankine panel method, are applied for the multi-level approach. IRF and Rankine panel method are based on the weakly nonlinear formulation which includes nonlinear Froude-Krylov and restoring forces. In the computation result of parametric roll occurrence test in regular waves, IRF and Rankine panel method show similar tendency. Although the GM variation approach predicts the occurrence of parametric roll at twice roll natural frequency, its frequency criteria shows a little difference. Nonlinear roll motion in bichromatic wave is also considered in this study. To prove the unstable roll motion in bichromatic waves, theoretical and numerical approaches are applied. The occurrence of parametric roll is theoretically examined by introducing the quasi-periodic Mathieu equation. Instability criteria are well predicted from stability analysis in theoretical approach. From the Fourier analysis, it has been verified that difference-frequency effects create the unstable roll motion. The occurrence of unstable roll motion in bichromatic wave is also observed in the experiment.

A new method for ship inner shell optimization based on parametric technique

  • Yu, Yan-Yun;Lin, Yan;Chen, Ming;Li, Kai
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.7 no.1
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    • pp.142-156
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    • 2015
  • A new method for ship Inner Shell optimization, which is called Parametric Inner Shell Optimization Method (PISOM), is presented in this paper in order to improve both hull performance and design efficiency of transport ship. The foundation of PISOM is the parametric Inner Shell Plate (ISP) model, which is a fully-associative model driven by dimensions. A method to create parametric ISP model is proposed, including geometric primitives, geometric constraints, geometric constraint solving etc. The standard optimization procedure of ship ISP optimization based on parametric ISP model is put forward, and an efficient optimization approach for typical transport ship is developed based on this procedure. This approach takes the section area of ISP and the other dominant parameters as variables, while all the design requirements such as propeller immersion, fore bottom wave slap, bridge visibility, longitudinal strength etc, are made constraints. The optimization objective is maximum volume of cargo oil tanker/cargo hold, and the genetic algorithm is used to solve this optimization model. This method is applied to the optimization of a product oil tanker and a bulk carrier, and it is proved to be effective, highly efficient, and engineering practical.