• Korean Journal of Optics and Photonics
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• v.24 no.3
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• pp.120-124
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• 2013

We propose a method to reconstruct the two-dimensional object from an image captured through an array of random lenses each of which has random shape, size, and focal power. In the proposed method, the characteristics of the random lens array are estimated by capturing images for known elementary inputs, and then the object is reconstructed by measuring correlations between the random lens images of the object and the elementary inputs. The experimental results show that the original object can be recognized by the proposed reconstruction method. Nevertheless, further quality enhancement is required to increase feasibility and to extend to general three-dimensional object cases.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.202-206
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• 2012

In this paper, we proposed on the direction of self-repairing mimicking the cell on the digital system design. Three-dimensional array of cells rather than using the original structure of FPGA, an array of blocks for efficient error detection methods were investigated. With a certain regularity, so the design method in detail by dividing the full array. The digital circuits can be detected fault location easily and quickly.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1306-1311
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• 2012

In this paper, we proposed on the direction of self-repairing mimicking the cell on the digital system design. Three-dimensional array of cells rather than using the original structure of FPGA, an array of blocks for efficient error detection methods were investigated. With a certain regularity, so the design method in detail by dividing the full array. The digital circuits can be detected fault location easily and quickly.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.17-21
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• 2003

In this paper, we design an optimal planar array geometry for maximum side-lobe reduction. The concept of thinned array is applied to obtain an optimal two dimensional(2-D) planar array structure. First, a 2-D rectangular array with uniform spacing is used as an initial planar array structure. Next, we modify the initial planar array geometry with the aid of thinned array theory in order to reduce the maximum side-lobe level. This is implemented by a genetic algorithm under some constraint, minimizing the maximum side-lobe level of the 2-D planar array. It is shown that the optimized planar array structure can achieve low side-lobe level without optimizing the excitations of the array antennas.

• Geophysics and Geophysical Exploration
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• v.4 no.3
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• pp.59-69
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• 2001

Five kinds of modified electrode arrays were proposed to overcome the weak points of the commonly used arrays using dipole and/or pole in two-dimensional resistivity surveys. The modified pole-pole array was suggested to overcome the inefficiency caused by distant earthing in pole-pole array. Four kinds of modified arrays using dipole were designed to enhance the signal-to-noise ratio of the conventional dipole-dipole and pole-dipole arrays through boosting up the measured potential difference. In the numerical experiments using the two-dimensional modeling and inversion, the effects of the ambient electrical noise and the resolving power were examined and the results showed the validity of the modified arrays proposed in this study.

• Journal of the Optical Society of Korea
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• v.9 no.3
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• pp.95-98
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• 2005

We propose a two-dimensional temporal/wavelength optical code division multiple access (OCDMA) encoder/decoder, which has an array of superstructured fiber Bragg gratings (SSFBGs). SSFBGs in an encoder/decoder have different wavelengths from each other and can be coded with the same OCDMA code or not. Simulation was performed to analyze the feasibility of the scheme.

• Journal of the Korean Society of Safety
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• v.18 no.4
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• pp.98-104
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• 2003

Various nondestructive evaluation (NDE) techniques have been studied to locate steel rebars of dowel, and to detect invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes. In this study, the aurhors developed 3-dimensional (3D) electromagnetic (EM) imaging technology to detect such damage and to identify exact location of steel rebars of dowel. The authors have developed sub-surface two-dimensional (2D) imaging technique using tomographic antenna array in previous works. In this study, extending the earlier analytical and experimental works on 2D image reconstruction, a 3D microwave imaging system using tomographic antenna array was developed, and multi-frequency technique was applied to improve quality of the reconstructed image and to reduce background noises. This paper presents the analytical expressions of numerical focusing procedures for 3D image reconstruction and numerical simulation to study the resolution of the system and the effectiveness of multi-frequency technique. Also, the design of 4?4 antenna array with switching devices is introduced as a preliminary study for the final design of whole array.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.21-26
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• 2005

In order to simulate the powder compaction process and to assess the effects of packing randomness and particle arrangement 2-dimensional model of rod array compaction using quasi-random multiparticle array is introduced. The elastic modulus of porous ceramics is computed by the homogenization method. With 3 Al₂O₃ and 3 Al particles the compaction processes associated with the porosities are simulated by the explicit finite element method, based on the elastic modulus found by the homogenization method. The simulation results are compared with both previous analytical ones and experimental measurements. Finally, in order to find the relationship between the friction coefficient of powder particles and the relative density, the sensitivity analysis is performed.

• Journal of IKEEE
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• v.26 no.1
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• pp.129-132
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• 2022

In this paper, a technique for optimizing the sub-array system structure that can minimize the side lobe level of the phased-array antenna is proposed. Optimization of the proposed array antenna structure is to adjust the spacing between sub-arrays and sub-arrays by using a hexagonal array structure of one sub-array and a hexagonal sub-array for six hexagonal arrays, and thus the entire phased array antenna system of the radiation pattern was optimized. Compared to the 2-dimensional planar antenna system, the proposed technique maintains a gain of 24.3 dBi and a half-power beam-width of 8.46 degrees without change, and only reduces -3.4 dB and -6.5 dB in the x-axis and y-axis directions, respectively.

• ETRI Journal
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• v.27 no.3
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• pp.273-279
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• 2005

Toward code division multiple access (CDMA) communications and data protection, we propose and analyze pseudorandom noise (PN) sequences generated from a 2-dimensional array structure of shift-registers. For any positive integers m and n, we construct PN sequences of period $2^{mm}-1$ using an $m{\times}n$ array of registers and show that we can generate all shifted PN sequences as required by IS-95x with the proper linear combination of available sequences.