• 제어로봇시스템학회:학술대회논문집
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• 1988.10b
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• pp.782-785
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• 1988

A two-dimensional positioning system by use of an M-array is proposed. An M-array pattern, which is known as one of the two-dimensional pseudorandom array, is attached on an object to be positioned. The M-array pattern is observed by a TV camera and crosscorrelated with the reference M-array. The maximum of the two-dimensional crosscorrelation function is sought by two-dimensional servo system. This method of positioning can be used in very noisy circumstances.

• The Transactions of the Korea Information Processing Society
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• v.6 no.3
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• pp.812-820
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• 1999

In two-dimensional dictionary matching problem, we are given a two-dimensional text T and a dictionary D={P\ulcorner, ...., P\ulcorner} as a set of two-dimensional patterns. We seek the locations of all the dictionary patterns that appear in T. We present a new two-dimensional pattern matching algorithm that can handle just a single pattern, and then show how to extend it into two-dimensional dictionary matching algorithm. The suggested algorithm is practical in the sense that it can deal that it uses a small extra space proportional to the size of the dictionary, and that it is quite simple to be implemented without depending on complicated data structures.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.77-84
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• 2013

In this paper, we review two-dimensional measuring methods referring to target patterns. The patterns consist of two linearly-repeated patterns or is designed repeatedly in two-dimension. The repeated properties are reflectivity, refractivity, air-gapping distance, capacitance, magnetic reluctance, electrical resistance and sloping gradient, etc. However, the optical methods are generally used for high speed processing and density, and their encoding principles are treated here. In case of two-dimensional pattern, as there is not inherently error between single units encoding the pattern except for the metrology frame errors, the end-effector position of an object accompanying the pattern can be measured with respect of the global frame without via error. Therefore, it is regarded as a substitute for laser interferometer with severe environmental constraints and has been applied to the high-accurate planar actuator.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1737-1741
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• 1991

The authors proposed a new two-dimensional(2D) positioning system by use of M-array and correlation technique which is suitable for noisy environment in '88KACC and its revised versions in '89KACC and '90KACC. This system uses the property of M-array that the autocorrelation function of the M-array has a sharp peak at its origin. In this paper, a new mark pattern is developed, instead of M-array, with which the two-dimensional positioning system becomes robust to rotation error of TV camera. The property of the rotation-free pattern is checked under various conditions, and it is shown that, by use of this rotation-free pattern, the positioning system can be used not only in a noisy environment but also in a roughly aligned set up of the TV camera.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.4
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• pp.303-309
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• 2008

Dense and fine polymer patterns often collapse, as they come into contact with each other at their protruding tips. Resist pattern collapse depends on the aspect ratio of patterns and the surface tension of rinsing materials. The pattern collapse is a very serious problem in microfabrication, because it is one of the factors which limit the device dimensions. The reasons for the pattern collapse are known as the surface tension of rinse liquid, centrifugal force and rinse liquid flow produced in the developing process. In this work, we tried to evaluate the pattern collapse of three-dimensional microstructures that were fabricated by two-photon induced photopolymerization, and showed the way how to reduce the deformation of microstructures.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.194-196
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• 2022

When electromagnetic wave transmitted from the radar antenna hits the target, a specific type of electric field is formed according to the electrical characteristics and appearance of the target, which is called an RCS pattern. There are various commercial programs that calculate the RCS of the target and plot the RCS pattern. For the analysis of large targets such as warships or ships, a program with a high frequency analysis method, which has a faster calculation speed than the low frequency analysis method is suitable. XGTD, a high-frequency analysis program, can quickly plot a two-dimensional RCS pattern for 360 degrees of a target, but a three-dimensional RCS pattern cannot be obtained. In this paper, it is proposed that a method of plotting two-dimensional RCS patterns of a target from various angles using XGTD, generating a three-dimensional RCS pattern using this, and converting it into a three-dimensional antenna pattern file.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.6
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• pp.515-521
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• 2003

There are now many theoretical investigations and real manufactures for numerous applications of photonic crystals (PCs) associated with photonic band gap and photonic integrated circuits. However, there are some difficulties to design and fabricate the desired pattern quality. It is not easy to satisfy accurate critical dimension (CD) for patterns with arbitrary shapes and pitch sizes aligned in various directions. In this work, we report the optimum conditions to better fabricate and design, and greatly improve pattern quality in delineating two-dimensional (2D) PCs in the nanometer range using single- step e-beam lithography system with conventional exposure mode.

• The Korean Journal of Ecology
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• v.13 no.2
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• pp.83-92
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• 1990

Two-dimensional analysis provides a comprehensive description of the structure, scales of pattern and directional components in a spatial data set. In spectral analysisi, four functions are illustrated,; the autocorrelation, the periodogram, the R-spectrum and the $\theta$ -spectrum. The R-spectrum and $\theta$ -spectrum function respectively summarize the periodogram in term of scale of pattern and directional components. Sampling is measured in the Naejang National Park area where the Daphniphyllum trees grow. 320 contiguous (15$\times$15)m plots are located along the transect and density of all trees over DBH 3 cm recorded respectively. 12 species of vascular plant are recorded in this survey area. The trend surface of density of all plant are estimated using polynomial regression and are exhibited in 3-dimensional graph and density contour map. Transformation to the corresponding polar spectrum from the periodogram emphasized the directional components and the scales to pattern. R-spectrum corresponding to the scale of pattern of periodogram showed a large peak 15.47 in the interval 9$\theta$-spectrum corresponding to directional components have two peaks 8.28 and 11.05 in the interval $35^{\circ}\theta <45^{\circ}and 125^{\circ}\theta< <135^{\circ}, respectively. Programs to compute all the analyses described in this study was obtained from Dr. Ranshow and was translated to BASIC by the author.

• Journal of the Korean Society for Nondestructive Testing
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• v.12 no.1
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• pp.16-24
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• 1992

Moire interferometry using a diffraction grating and a laser is a powerful technique for analizing small deformation of a specimen. In the method, the x and y-directional fringe patterns are obtained by using the x and y-directional sets of two beams. If the both sets of two beams are simultaneously incident to the specimen, the x and y-directional fringe patterns are super imposed. In this case, it is difficult to separate each directional fringe pattern. Therefore each fringe pattern has been separately recorded by selecting each set of two beams. In order to analyze a two-dimensional strain changing with time, Moire interferometry using the two-dimensional fourier transform method is proposed and the x and y-directional fringes are separated. By this method, the thermal deformation of a glass plate is analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.1-7
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• 2000

Generally, one-dimensional fiber optic code-division multiple-access(CDMA) system is encoded and decoded using optical orthogonal codes(OOC’s), where two-dimensional fiber optic CDMA system uses optical orthogonal signature pattern codes(OOSPC’s) for parallel data link process. The OOSPC’s should have good autocorrelation and cross-correlation properties. However, if timing information or synchronization of OOSPC’s can be obtained by other means, the property of autocorrelation may not be restricted and we can increase the number of pattern codes. In this paper we introduce the fiber optic CDMA system for parallel transmission of two-dimensional data and investigate methods of generation of two-dimensional pattern codes. The probability density function of interference noise is calculated in interfering OOSPC’s of the users and the corresponding bit error rate is derived.. We compare each OOSPC’s by plotting bit error rate versus threshold values and the number of simultaneous users, from the result, we propose the optimal OOSPC’s conditions for the parallel transmission of two-dimensional data.