• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1579-1589
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• 2013

We provide a step-by-step, easy-to-follow procedure for the method of controlled Lagrangian systems. We apply this procedure to solve the energy shaping problem for four benchmark examples: the inertial wheel pendulum, an inverted pendulum on a cart, the system of ball and beam and the Furuta pendulum.

• International Journal of Aeronautical and Space Sciences
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• v.3 no.2
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• pp.46-58
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• 2002

An inverse method is introduced to construct benchmark problems for the numerical solution of initial value problems. Benchmark problems constructed through this method have a known exact solution, even though analytical solutions are generally not obtainable. The solution is constructed such that it lies near a given approximate numerical solution, and therefore the special case solution can be generated in a versatile and physically meaningful fashion and can serve as a benchmark problem to validate approximate solution methods. A smooth interpolation of the approximate solution is forced to exactly satisfy the differential equation by analytically deriving a small forcing function to absorb all of the errors in the interpolated approximate solution. A multi-variable orthogonal function expansion method and computer symbol manipulation are successfully used for this process. Using this special case exact solution, it is possible to directly investigate the relationship between global errors of a candidate numerical solution process and the associated tuning parameters for a given code and a given problem. Under the assumption that the original differential equation is well-posed with respect to the small perturbations, we thereby obtain valuable information about the optimal choice of the tuning parameters and the achievable accuracy of the numerical solution. Illustrative examples show the utility of this method not only for the ordinary differential equations (ODEs) but for the partial differential equations (PDEs).

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.11
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• pp.94-104
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• 1995

In this paper, we present a new multi-level logic synthesis method for producing the multi-level circuits which can be easily tested by the pseudoexhaustive testing techniques. The method consists of four stages. In the first stage, it generates the minimum variable supports for each output of a multiple-output function. In the second stage, it removes the minimum variable supports which if used to implement the outputs, lead to inefficient pseudoexhaustive test. In the third stage, it determines the minimum variable support and logic (uncomplementary or complementary logic) for each output. In the fourth stage, it performs the multi-level logic synthesis so that each output. In the fourth stage, it performs the multi-level logic synthesis so that each output has the minimum variable support and logic determined in the third stage. To evaluate the performance and quality of the proposed method, we have experimented on the 56 benchmark examples. The results show that for 56 examples, our method obtains better results than MIS in terms of testability. Moreover, the method produces better results for 19 examples and the same results for 12 examples compared with MIS in terms of literal count although it has been developed to improve the testability.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.2099-2106
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• 2018

This study presents a novel approach of discriminative feature vectors based on manifold learning using nonlinear dimension reduction (DR) technique to improve loss function, and combine with the Adversarial examples to regularize the object function for image classification. The traditional convolutional neural networks (CNN) with many new regularization approach has been successfully used for image classification tasks, and it achieved good results, hence it costs a lot of Calculated spacing and timing. Significantly, distrinct from traditional CNN, we discriminate the feature vectors for objects without empirically-tuned parameter, these Discriminative features intend to remain the lower-dimensional relationship corresponding high-dimension manifold after projecting the image feature vectors from high-dimension to lower-dimension, and we optimize the constrains of the preserving local features based on manifold, which narrow the mapped feature information from the same class and push different class away. Using Adversarial examples, improved loss function with additional regularization term intends to boost the Robustness and generalization of neural network. experimental results indicate that the approach based on discriminative feature of manifold learning is not only valid, but also more efficient in image classification tasks. Furthermore, the proposed approach achieves competitive classification performances for three benchmark datasets : MNIST, CIFAR-10, SVHN.

• Architectural research
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• v.15 no.4
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.7
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• pp.9-17
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• 1997

This paper proposes a routing model based on the HVHD for four-layer routing problems. Differing from the HVHV and HVHH models, the proposed HVHD model permits diagonal routing on the fourth laye rwith a grid of 45.deg., 90.deg. and 135.deg. directions. The developed algorithm which uses a channel-graph including weights routes a layer using diagonal model and the othe rthree layers using HVH model. Applications to several benchmark examples verify that approximately 10~25 percent reduction of channel density can be achieved compared to the conventional four-layer channel routing algorithms.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.261-268
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• 2003

A first order shear deformable Loop-subdivision triangular element which can handle transverse shear deformation of moderately thick shell is developed. The developed element is general since it includes the effect of transverse shear deformation and has standard six degrees of freedom per node.(three translations and three rotations) The quartic box-spline function is employed as interpolation basis function. Numerical examples for the benchmark problems are analyzed in order to assess the performance of the newly developed subdivision shell element. Both in the uniform and in the distorted mesh configurations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.9
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• pp.1230-1243
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• 1997

A numerical technique for simulating incompressible viscous flow with free surface is presented. The flow field is obtained by penalty finite element formulation. In this work, a modified volume of fluid (VOF) method which is compatible with 4-node element is proposed to track the moving free surface. This scheme can be applied to irregular mesh system, and can be easily extended to three dimensional geometries. Numerical analyses were done for two benchmark examples, namely the broken dam problem and the solitary wave propagation problem. The numerical results were in close agreement with the existing data. Illustrative examples were studied to show the effectiveness of the proposed numerical scheme.

• Steel and Composite Structures
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• v.9 no.6
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• pp.535-555
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• 2009

The harmony search method based optimum design algorithm is presented for geometrically non-linear semi-rigid steel frames. Harmony search method is recently developed metaheuristic algorithm which simulates the process of producing a musical performance. The optimum design algorithm aims at obtaining minimum weight steel frames by selecting from standard set of steel sections such as European wide flange beams (HE sections). Strength constraints of Turkish Building Code for Steel Structures (TS648) specification and displacement constraints were used in the optimum design formulation. The optimum design algorithm takes into account both the geometric non-linearity of the frame members and the semi-rigid behaviour of the beam-to-column connections. The Frye-Morris polynomial model is used to calculate the moment-rotation relation of beam-to-column connections. The robustness of harmony search algorithm, in comparison with genetic algorithms, is verified with two benchmark examples. The comparisons revealed that the harmony search algorithm yielded not only minimum weight steel frames but also required less computational effort for the presented examples.

• Steel and Composite Structures
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• v.8 no.6
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• pp.475-490
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• 2008

A hybrid tabu-simulated annealing algorithm is proposed for the optimum design of steel frames. The special character of the hybrid algorithm is that it exploits both tabu search and simulated annealing algorithms simultaneously to obtain near optimum. The objective of optimum design problem is to minimize the weight of steel frames under the actual design constraints of AISC-LRFD specification. The performance and reliability of the hybrid algorithm were compared with other algorithms such as tabu search, simulated annealing and genetic algorithm using benchmark examples. The comparisons showed that the hybrid algorithm results in lighter structures for the presented examples.