• International Journal of CAD/CAM
• /
• v.7 no.1
• /
• pp.21-30
• /
• 2007

The inverse offset method (IOM) is widely used for generating cutter paths from the point-based surface where the surface is characterised by a set of surface points rather than parametric polynomial surface equations. In the IOM, cutter path planning is carried out by specifying the grid sizes, called the step-forward and step-interval distances respectively in the forward and transverse cutting directions. The step-forward distance causes the chordal deviation and the step-forward distance produces the cusp. The chordal deviation and cusp are also functions of local surface slopes and curvatures. As the slopes and curvatures vary over the surface, different step-forward and step-interval distances are appropriate in different areas for obtaining the machined surface accurately and efficiently. In this paper, the chordal deviation and cusp height are calculated in consideration with the surface slopes and curvatures, and their combined effect is used to estimate the machined surface error. An adaptive grid generation algorithm is proposed, which enables the IOM to generate cutter paths adaptively using different step-forward and step-interval distances in different regions rather than constant step-forward and step-interval distances for entire surface.

• Journal of Aerospace System Engineering
• /
• v.8 no.4
• /
• pp.18-23
• /
• 2014

In preliminary design phase, the wing geometry of the civil aircraft was determined using the empirical equation and historical data. To make wing geometry more aerodynamically efficient, an aerodynamic shape optimization was conducted. For this purpose the parametric modeling, high fidelity CFD analysis and metamodel-based optimal design technique were adopted. The parametric modeling got the design process to achieve the improvement by generating the configuration outputs easily for the major design variables. The optimal design equations were formularized as the type of the multi-objective functions considering low/high speed and lift/drag coefficient. The optimal solution was explored with the help of the kriging metamodel and the desirability function, therefore the optimal wing planform was sought to be excellent at both low and high speed region. Additionally the optimal wing planform was validated that it was excellent not only at the specific AOA, but also all over the range of AOA.

• Journal of the Korea Computer Graphics Society
• /
• v.9 no.3
• /
• pp.15-21
• /
• 2003

An algorithm is developed for augmenting a real video with virtual graphics objects without computing Euclidean information. Real motion of the camera is obtained in affine space by a direct linear method using image matches. Then, virtual camera is provided by determining the locations of four basis points in two input images as initialization process. The four pairs of 2D location and its 3D affine coordinates provide Euclidean orthographic projection camera through the whole video sequence. Our method has the capability of generating views of objects shaded by virtual light sources, because we can make use of all the functions of the graphics library written on the basis of Euclidean geometry. Our novel formulation and experimental results with real video sequences are presented.

• 전기의세계
• /
• v.21 no.5
• /
• pp.7-12
• /
• 1972

Applying the theory of physiology and control systems, the visual system was studied as a regulator of impining light. The characteristics function of visual system is mainly analysed by spato-temporal characteristics based upon Enroth's model, Broca-Sulzer phenomenon and Mach effect. Some aims of this paper are as follows. (1) In order to get the excitatory and inhibitory potential of the intermediated cell layer in the retina, the exponential value, {exp(FM/kT)- $I_{mn}$ } is caculated based on the physiological theory in neuro-phenomena. (2) To show the visual characteristics by analog simulation for generating stimulus waveforms and analysis, the visual adaptation was recorded as electrical stimulation in the form of step functions. Furthermore, ti is shown that the above experimental data agrees satisfactorily with the theoretical (psychophysiological) values. This study is expected to lead to further studies concerned with human observer and human operator in control and especially pattern recognition systems.stems.

• Journal of electromagnetic engineering and science
• /
• v.8 no.1
• /
• pp.6-11
• /
• 2008

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

• IE interfaces
• /
• v.13 no.4
• /
• pp.591-598
• /
• 2000

In this paper, an efficient algorithm is proposed to find parting lines(PL) and generate parting surfaces(PS) for an injection mold design. We used a Face-Edge Graph which can be made by B-rep information of solid model. The graph is useful for finding the peripheral-loop edges for PL and the inner-loop edges for hole-patch. The PS can be generated automatically by selecting pre-defined direction lines. We can create a core and cavity molds by trimming the raw stock block with the PS and the upper/lower faces of a product model. We implemented proposed method with Unigraphics API functions and C language, and tesed on Unigraphics V15.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.37 no.4
• /
• pp.226-231
• /
• 1988

A program is developed for generating the dynamic equations for the robotic manipulators using the symbolic language muSIMP/ MATH. The muSIMP/ MATH is a LISP-based computer. algebra package, devoted to the manipulation of algebraic expressions including numbers, variables, functions, and matrices. The muSIMP-MATH can operate on personal computer such as IBM-PC. The program is developed, based on the Lagrange-Euler formulation. This program is applicable to the manipulators with any number of degrees of freedom, and maximum number of degrees of freedom is set to be six in this program.

• IE interfaces
• /
• v.13 no.2
• /
• pp.157-165
• /
• 2000

In this paper, an efficient method is proposed to place the cooling lines(CLS) and ejector pins(EPS) of mold design. The other components of mold, except CLS and EPS, can be generated automatically by batch processing. But the placements and sizes of CLS and EPS depend on the shapes of a part, so that the design works of CLS and EPS should be processed interactively. Using the pre-defined reference points, the positions of CLS and EPS can be determined interactively. By the proposed method, the interference occurred during placing CLS and EPS can be avoided, and the proper lengths of them can be calculated automatically. The information of the positions and lengths are stored in BOM database for generating a machining data. The proposed method is implemented with Unigraphics API functions and C language, tested on Unigraphics V15.

• 연구논문집
• /
• s.22
• /
• pp.47-54
• /
• 1992

A problem of relevant interest to some industries is that of optimum two-dimensional layout. The objective of this work is to allocate the shapes on a sheet in such a way to minimize the amount of waste. A nesting software has been developed to help user arrange the 2D parts effectively. It provides various functions, e.g., transformation, distance-check, NC post-processor, etc. This software is developed in X window system with C langusge. Final goal of this software is generating NC code data of the 2D parts on the sheet that can be directly used in NC machines.

• Proceedings of the KSRS Conference
• /
• 2002.10a
• /
• pp.786-791
• /
• 2002

Mapping systems using Satellite Imagery has not been well-established compare to conventional Arial Photograph mapping systems. In order for satellite imagery to produce a stable quality of maps, it requires to follow the standard mapping procedures. In this satellite imagery study, we proposed four methods of mapping procedures. Mapping methods were established by generating trial maps and analyzing types of input data and functions of DPW (Digital Photogrammetric Workstation). On quantitative aspect, accuracy of each steps were measured by increasing 2 GCPs each time from the minimum of 6 GCPs. In DLT, with the minimum of 10 points, RMSE is 2 pixels at most. Besides that, interpretation and stereoscopic plotting using KOMPSAT-1 imagery and other simulated imagery was performed. The tests resulted that, for KOMPSAT-1 (6.6m) stereoscopic images, the possibility of interpretation is 44.79% and possibility of stereoscopic plotting is 43.75%. In the other hand, for simulated imagery (1m), the possibility of interpretation is 60.92% and possibility of stereoscopic plotting is 55.18%.