• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.13-14
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• 2000

21.6" a-Si:H TFT array for direct conversion X-ray detector with 2480 by 3072 pixel is successfully developed. To obtain good X-ray image quality, novel structure, storage on BCB structure, is proposed. The structure reduces the parasitic capacitance of data line, one of the main sources of signal noise. Also, the structure shows higher failure resistance against defects than that of the old design.

• Korean Journal of Computational Design and Engineering
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• v.14 no.4
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• pp.217-224
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• 2009

Most divide-and-conquer implementations for Delaunay triangulation utilize quad-edge or winged-edge data structure since triangles are frequently deleted and created during the merge process. How-ever, the proposed divide-and-conquer algorithm utilizes the array based data structure that is much simpler than the quad-edge data structure and requires less memory allocation. The proposed algorithm has two important features. Firstly, the information of space partitioning is represented as a permutation vector sequence in a vertices array, thus no additional data is required for the space partitioning. The permutation vector represents adaptively divided regions in two dimensions. The two-dimensional partitioning of the space is more efficient than one-dimensional partitioning in the merge process. Secondly, there is no deletion of edge in merge process and thus no bookkeeping of complex intermediate state for topology change is necessary. The algorithm is described in a compact manner with the proposed data structures and operators so that it can be easily implemented with computational efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.5
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• pp.981-989
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• 1997

In this paper, the 5-element active phased array antennas coupled through slotline between elements are designed and fabricated. A recent studies on the active phased array antennas using the transmission line coupling which can be designed to provide strong coupling and the appropriate coupling phase. But this sturucture has limitation of expanding in two dimensions for planar active phased array antennas and distortion of the radiation pattern caused by coupling network. Thus our work proposes the slotline coupling structure asthe broadband coupling network for the active phased array antenna. In experiment, 5-elements active phased array antenas have steering range from -30.deg. to 20.deg. off broadside as the free-running frequencies of end elements are controlled. The overall results show that the proposed slotline coupling structure is suited for the coupling network in the actie phased array antenna system. And the proposed coupling structire solves the expansion problem and eliminates the distortion of the radiation pattern caused by the spurious radiation of the transmission line coupling network. Thus thiscan be expanded to two dimensional coupling network for the planar active phased array antenna system.

• The Journal of the Acoustical Society of Korea
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• v.27 no.6
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• pp.263-270
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• 2008

The performance of an ultrasonic array sensor is determined by the properties of constituent materials and the effects of many structural parameters. In this study, with the finite element method, variation of the performances of an ultrasonic array sensor was analyzed in relation to its structural variables. Based on the analysis result, the structure of the ultrasonic array sensor was optimized to provide the highest sensitivity while satisfying such requirements as fractional bandwidth, center frequency and -20 dB pulse length. The optimization was carried out with the SQP-PD method for a target function composed of the ultrasonic array sensor performance. The optimized ultrasonic array sensor satisfied all the required specifications to be applicable to medical imaging diagnosis. The design technology in this paper can be utilized for other ultrasonic array sensors of a similar structure.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.5
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• pp.73-80
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• 1994

This paper deals with a new design scheme to reduce the array multiplication time by modifing the structure of the CSA array in the conventional array miltyplier. A circuit with the suggested scheme is designed and simulated. The suggested scheme is to assign the inputs of addend and augend faster than carry input to the CSA. It is shown that the operation time of the CSA array is reduced to 50%.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.416-418
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• 1996

A $50{\times}50{\mu}m^2$ aluminum micromirror array is fabricated using surface micromachining technology. $50{\times}50$ micromirrors are arrayed two dimensionally. The micromirror plate is supported by a vertical spring structure that is placed underneath the mirror plate. When the mirror plates reflect a light, the micromirror array un have large effective reflecting area. Fabrication of vertical spring uses only one mask and shadow evaporation process.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.3
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• pp.242-247
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• 2009

The ability of time reversal techniques to focus ultrasonic beams on the source location is important in many aspects of ultrasonic nondestructive evaluation. In this paper, we investigate the time reversal beam focusing of ultrasonic array sensors on a defect in layered media. Numerical modeling is performed using the commercially available software which employs a time domain finite difference method. Two different time reversal approaches are considered - the through transmission and the pulse-echo. Linear array sensors composed of N elements of line sources are used for signal reception/excitation, time reversal, and reemission in time reversal processes associated with the scattering source of a side-drilled hole located in the second layer of two layer structure. The simulation results demonstrate the time reversal focusing even with multiple reflections from the interface of layered structure. We examine the focusing resolution that is related to the propagation distance, the size of array sensor and the wavelength.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.860-867
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• 2009

In this paper, we designed the array antenna for FMCW radar in X - band frequency, and we chose stacked structure for improvement of narrow bandwidth. The array antenna is implemented on the circuit board which is relative permittivity 2.33 and the stacked patchs are designed on the circuit board which is relative permittivity 4.6. A Foam which has a similar permittivity of air is added to keep the particular gap between array antenna and the stacked patch. The result of array antenna has characteristics that a half-power beam width is $10.6^{\circ}$ and antenna gain is 18.70 dBi and bandwidth is 1.25GHz at the design frequency of 9GHz. The result of the array antenna with the stacked structure has that the half power beam width is $15.17^{\circ}$ and the antenna gain is 15.85dBi and bandwidth is 2GHz. It is needed to improve the antenna gain as keeping bandwidth in same level.

• Journal of Power Electronics
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• v.16 no.2
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• pp.631-642
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• 2016

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system.

• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.277-280
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• 2002

This paper analyze the characteristics of three multipliers in finite fields GF(2m) from the point of view of processing time and area complexity. First, we analyze structure of three multipliers; 1) LSB-first systolic array, 2) LFSR structure, and 3) CA structure. To make performance analysis, each multiplier was modeled in VHDL and was synthesized for FPGA implementation. The simulation results show that LFSR structure is best from the point of view of area complexity, and LSB systolic array is best from the point of view of processing time per clock.