• Structural Engineering and Mechanics
• /
• v.17 no.6
• /
• pp.767-788
• /
• 2004

The classical 8-node isoparametric serendipity element uses parametric shape functions for both test and trial functions. Although this element performs well in general, it yields poor results under severe mesh distortions. The distortion sensitivity is caused by the lack of continuity and/or completeness of shape functions used for test and trial functions. A recent element using parametric and metric shape functions for constructing the test and trial functions exhibits distortion immunity. This paper discusses the choice of parametric or metric shape functions as the basis for test and/or trial functions, satisfaction of continuity and completeness requirements, and their connection to distortion sensitivity. Also, the performances of four types of elements, viz., parametric, metric, parametric-metric, and metric-parametric, are compared for distorted meshes, and their merits and demerits are discussed.

• Structural Engineering and Mechanics
• /
• v.29 no.3
• /
• pp.289-300
• /
• 2008

The use of metric trial functions to represent the real stress field in what is called the unsymmetric finite element formulation is an effective way to improve predictions from distorted finite elements. This approach works surprisingly well because the use of parametric functions for the test functions satisfies the continuity conditions while the use of metric (Cartesian) shape functions for the trial functions attempts to ensure that the stress representation during finite element computation can retrieve in a best-fit manner, the actual variation of stress in the metric space. However, the issue of how to handle situations where there is locking along with mesh distortion has never been addressed. In this paper, we show that the use of a consistent definition of the constrained strain field in the metric space can ensure a lock-free solution even when there is mesh distortion. The three-noded Timoshenko beam element is used to illustrate the principles. Some significant conclusions are drawn regarding the optimal strategy for finite element modelling where distortion effects and field-consistency requirements have to be reconciled simultaneously.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.36 no.4
• /
• pp.252-258
• /
• 1987

Time periodic finite element solutions for sinusoidally excited electromagnetic field problems in moving media are presented. Solutions by the Galerkin method contain spurious oscillations when grid Peclet number is more than one. To suppress these oscillations an upwind finite element method using two different time periodic test functions is introduced. One is multiplied to second and first-order space derivative terma and the other to the time derivative term. Test functions are obtained from trial functions by adding or subtracting quadratic bias functions with appropriate scaling factors. Phase differences are considered between trial functions and bias functions. For simple interpretations of the phase differences, complex scaling factors are used. The proposed method is developed to give nodally exact solutions for uniform grid spacing in one dimensional problems. Based on the one dimensional results, a two dimensional upwinding scheme is also derived.

• Publications of The Korean Astronomical Society
• /
• v.24 no.1
• /
• pp.65-81
• /
• 2009

We present the performance test results of VLBI Correlation Subsystem (VCS) trial product which was being developed for 1 year from August 2007. It is a core component of Korea-Japan Joint VLBI Correlator (KJJVC). The aim for developing VCS trial product is to improve the performance of VCS main product to reduce the efforts and cost, and to solve the design problems by performing the preliminary test of the manufactured trial product. The function of VCS trial product is that it is able to process the 2 stations-1 baseline, 8 Gbps/station speed, 1.2 Gbps output speed with FX-type. VCS trial product consists of Read Data Control Board (RDC), Fourier Transform Board (FTB), and Correlation and Accumulation Board (CAB). Almost main functions are integrated in the FTB and CAB board. In order to confirm the performance of VCS trial product functions, the spectral analysis, delay compensation and correlation processing experiments were carried out by using simulation and real observation data. We found that the overflow problem of re-quantization after FFT processing was occurred in the delay compensation experiment. We confirmed that this problem was caused by valid bit-expression of the re-quantized data. To solve this problem, the novel method will be applied to VCS main product. The effectiveness of VCS trial product has been verified through the preliminary experimental results, but the overflow problem was occurred.

• Journal of Ocean Engineering and Technology
• /
• v.3 no.2
• /
• pp.570-570
• /
• 1989

The natural frequencies of a rectangular plate on non-homogeneous elastic foundations were obtained by using the Ritz method and Galerkin method. The results of both methods using the different type of trial functions were also compared. Furthermore, the effects of the variation of boundary conditions, the stiffness of the foundation spring, the dimension ratio of the plate were investigated. As a result, the Galerkin method can be used to obtain the accurate solution and can be effectively used to design the foundation bed.

• Journal of Ocean Engineering and Technology
• /
• v.3 no.2
• /
• pp.70-76
• /
• 1989

The natural frequencies of a rectangular plate on non-homogeneous elastic foundations were obtained by using the Ritz method and Galerkin method. The results of both methods using the different type of trial functions were also compared. Furthermore, the effects of the variation of boundary conditions, the stiffness of the foundation spring, the dimension ratio of the plate were investigated. As a result, the Galerkin method can be used to obtain the accurate solution and can be effectively used to design the foundation bed.

• Journal of applied mathematics & informatics
• /
• v.29 no.3_4
• /
• pp.653-668
• /
• 2011

This paper presents a new hybrid method for solving nonlinear complementarity problems with $P_0$-functions. It can be regarded as a combination of smoothing trust region method with ODE-based method and line search technique. A feature of the proposed method is that at each iteration, a linear system is only solved once to obtain a trial step, thus avoiding solving a trust region subproblem. Another is that when a trial step is not accepted, the method does not resolve the linear system but generates an iterative point whose step-length is defined by a line search. Under some conditions, the method is proven to be globally and superlinearly convergent. Preliminary numerical results indicate that the proposed method is promising.

• The Journal of the Korea Contents Association
• /
• v.16 no.5
• /
• pp.601-611
• /
• 2016

As oral trial principle and civil participation in criminal trials spread, the environment of Korean courtroom is in need of a systematic introduction of trial presentation which can supplement with the oral trial presentation's weakness. Therefore this study analyzes the definition, types, and effectiveness of trial presentation, considering characters of the Korean court's environment. As for following research step, the most widely used trial presentation softwares in the USA and Korea are analyzed and compared in consideration of the particularity of the trial presentation. Based on this analysis, this study suggested elements to be included in the presentation software optimized for Korean court's environment as follows: 1. Ease of the insertion of various forms and media, 2. Appropriate limitation of the spectrum for graphic style, 3. Ease of use of graphics tools, 4. System functions. Such a suggestion was proposed not only to enhance the clarity, accuracy, effectiveness in developing insistence and delivery of content, but also promote aesthetic quality and consistency of presentation's visual communication aspect.

• 한국기계연구소 소보
• /
• s.10
• /
• pp.79-97
• /
• 1983

This report includes the general descriptions on the Cavitation Tunnel, newly installed at the Ship Research Station, KIMM, and also on the functions and operating procedures of the major measuring equipments. It also includes the results of the trial operation of the Tunnel and testing techniques in the Cavitation Tunnel.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.20 no.2
• /
• pp.176-187
• /
• 2007

Purpose: Recent studies show that Skin Resistance Variability(SRV) could be related to the functions of Hypothalamus-Pituitary-Ovary(H-P-O) axis. 7-Zone-Diagnostic System is oriental medicine measuring system using SRV. To know the differences of SRV of normal and abnormal menstrual cycle groups, we research the SRV of the two groups. Methods: We measured SRV of two groups that were consist of 126 women who took CP-6000A test in Sangji Oriental Medical Hospital from Mar. 2004 to Feb. 2006. After detection of SRV, we performed correlation analysis by SPSS 12.0. Results: The SRV was measured twice in 7 areas. By the results of 1st trial on Factor AA of the SRV, the patient group's results were lower than normal group's results in all 7 areas. And there were remarkable differences in 1, 2, 3, 4, 5, 7 areas between two groups. By the results of 2nd trial on Factor AA of the SRV, the patient group's results were lower than normal group's results in all 7 areas similar to 1st trial results. And there were remarkable differences in 2, 3 areas between two groups. Conclusion: Comparing normal group with patient group, these results may reflect the relations of abnormal menstrual cycle and H-P-O axis functions. Because patient's results were lower than normal's in all 7 areas. And remarkable different results in 2, 3 areas were repeated by twice trial all. Further study will be needed.