• Journal of Internet of Things and Convergence
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• v.9 no.3
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• pp.81-86
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• 2023

SSD (solid state disk), which is flash memory-based storage device, has the advantages of high density and fast data processing. Therefore, it is being utilized as a storage device for high-capacity data storage systems that manage rapidly increasing big data. However, flash memory, a storage media, has a physical limitation that when the write/erase operation is repeated more than a certain number of times, the cells are worn out and can no longer be used. In this paper, we propose a method for converting defective multi-bit cells into single-bit cells to reduce the defect rate of flash memory and extend its lifetime. The proposed idea distinguishes the defects and treatment methods of multi-bit cells and single-bit cells, which have different physical characteristics but are treated as the same defect, and converts the expected defective multi-bit cells into single-bit cells to improve the defect rate and extend the overall lifetime. Finally, we demonstrate the effectiveness of our proposed idea by measuring the increased lifetime of SSD through simulations.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.251-257
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• 2017

In this paper, an algorithm for detecting defects in thin-film-transistor liquid-crystal display (TFT-LCD) cell images is presented. TFT-LCD cell images typically contain periodic cell patterns that make it difficult to detect defects. We propose an efficient and powerful algorithm for eliminating the cell patterns using magnitude spectrum analysis. The first step was to obtain a spectrum for a cell image using the Fourier transform while eliminating larger coefficients using an adaptive filter. Next, an image without the cell pattern was obtained by using the inverse Fourier transform. Finally, the defect pixels were detected using the STD algorithm. The validity of the proposed method was investigated using real TFT-LCD cell images. The experimental results indicate that the proposed technique is extremely effective for detecting defects in TFT-LCD cell images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.23-29
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• 2010

This paper presents a method for constructing a memory system using defective memory chips comprising faulty storage blocks. The three-dimensional memory system introduced here employs a die-stacked structure of faulty memory chips. Signals lines passing through the through-silicon-vias (TSVs) connect chips in the defect tolerant structure. Defective chips are classified into several groups each group comprising defective chips having faulty blocks at the same location. A defect tolerant memory system is constructed using chips from different groups. Defect-free storage blocks from spare chips replace faulty blocks using additional routing circuitry. The number of spare chips for defect tolerance is $s={\ulcorner}(k{\times}n)/(m-k){\urcorner}$ to make a system defect tolerant for (n+s) chips with k faulty blocks among m independently addressable blocks.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.5
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• pp.432-437
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• 2008

This paper proposes a defect cell extraction algorithm for TFT-LCD auto-repair system. Auto defect search algorithm and automatic defect cell extraction method are very important for TFT-LCD auto repair system. In the previous literature[1], we proposed an automatic visual inspection algorithm of TFT-LCD. Based on the inspected information(defect size and defect axis, if defect exists) by the automatic search algorithm, defect cells should be extracted from the input image for the auto repair system. For automatic extraction of defect cells, we used a novel block matching algorithm and a simple filtering process in order to find a given reference point in the LCD cell. The proposed defect cell extraction algorithm can be used in all kinds of TFT-LCD devices by changing a stored template which includes a given reference point. Various experimental results show the effectiveness of the proposed method.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.12
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• pp.24-30
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• 2010

In recent memories, repair is an unavoidable method to maintain its yield and quality. The probability of defect occurence on spare lines has been increased through the growth of the density of recent memories with 2 dimensional spare architecture. In this paper, a new analysis region virtualization scheme is proposed. the analysis region virtualization scheme can be applied with any BIRA (built-in redundancy analysis) algorithms without the loss of their repair rates. The analysis region virtualization scheme can be a viable solution for BIRA considering the faulty spare lines of the future high density memories.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.168-169
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• 2022

As the electric vehicle market has grown rapidly, the battery market has grown exponentially. Due to the gap between the generation speed of quality control technology and battery mass production speed for batteries mounted on electric vehicles, many durability problems have arisen for batteries. Most accidents are caused by electrical factors, but there is no technology to quickly inspect them. In this paper, we are going to propose a quick analysis of battery cell defects using the GAN model.

• Journal of the Korea Society of Computer and Information
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• v.7 no.4
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• pp.174-181
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• 2002

In this Paper, we proposed the method for the TIT (Theoretical Inter-arrival Time) was suggested in which it saves the cells by using the data buffer in the system rather than by using one separately from the internal controller, and it also releases these cells saved. The method of TIT complements the defect of the accumulation of the delay in the method of RDT which considers the time of the cell that is discharged from the established cell interval controller. And, in order to apply the merit of RDT, the method of TIT sets its standards on the cells arrival time as it was in the method of RAT.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1310-1310
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• 2015

대단위 태양광 발전소 또는 고층건물에 설치된 태양광 모듈의 결함을 분석하는데 있어 열화상 카메라를 통한 온도로써 태양광 모듈의 결함을 검출하는 방식이 대두되고 있다. 본 논문에서는 열화상 카메라로 얻은 영상을 온도로 표현하는데 필요한 영상처리를 각각의 태양광 모듈들을 셀 단위로 분류하고 해당 셀을 기준으로 행 이미지를 ROI로 잡은 후 이미지 저장을 하는 방법을 제안한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.2
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• pp.147-153
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• 2009

In this paper, FSS(Frequency Selective Surface) using defect mode characteristic is proposed. The unit cell using defect mode characteristic of the proposed FSS is offered lower resonant frequency in the same cell size. The number of suitable array is optimized 13 by 13. Also, the patch antennas operated in WCDMA(Wideband Code Division Multiple Access) Tx band and Rx band are designed for the comparison. The gain value of proposed FSS-1 complex structure (the patch antenna of Tx band and FSS) is improved 3.3 dB from 9.98 dBi to 13.28 dBi in Tx band. The gain value of proposed FSS-2 complex structure(the patch antenna of Rx band and FSS) is improved 5.53 dB from 9.81 dBi to 15.34 dBi in Rx band. Also the measured impedance bandwidth($VSWR{\leq}2$) of manufactured $13{\times}13$ array antenna is from 337 MHz(1.87 to 2.21 GHz). The measured radiation gain is 11.39 dBi(1.94 GHz), 13.11 dBi(2.05 GHz), 11.09 dBi(2.14 GHz). The measured radiation efficiency is 81 %. Because the proposed FSS structure has more higher gain, it will be applied to antenna of WCDMA repeater system.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.81.1-81.1
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• 2010

SOFC 발전시스템의 상용화를 위해 선행되어야 할 것은 스택의 안정적 출력 및 신뢰성 확보이다. 이를 이루기 위해서는 스택을 구성하는 구성요소의 신뢰성 있는 규격 및 검수가 필요하다. 즉, 셀, 밀봉재, 분리판 및 집전체로 대변되는 구성요소들이 스택에 장착되었을 때 그 기능을 최대한 발휘하면서도 점진적 또는 급격한 품질저하가 발생되지 말아야 한다. 특히, 셀의 경우 스택의 성능에 직접적인 영향을 미치는 구성요소로서 품질에 대한 명확한 검수기준이 필요하다. SOFC용 셀은 다공성 anode, 치밀한 전해질, 그리고 다공성 cathode로 구성된 세라믹 소결체이다. 이 때 치밀한 전해질에 결함이 내재되어 있거나 물리적 힘에 의해 신규로 발생할 경우, 연료로 사용되는 수소와 공기가 만나는 cross-over가 발생하게 된다. Cross-over는 연료가 소모되는 문제도 있지만 발열로 인한 Hot spot을 형성시켜서 주변과의 온도구배를 유발하고, 이로 인해 고체 전해질의 균열전파를 일으킬 수 있고 나아가 급격한 셀의 파괴를 야기할 수 있다. 본 연구에서는 SOFC에 사용되는 셀의 형상측정, 물리적 강도 및 결함 검출을 위한 검수기법을 개발하여 스택의 신뢰성 향상과 향후 규격표준화를 위한 기반을 제공하고자, 평판형 셀의 3차원 형상을 정밀하게 측정하는 장치와 일정 면압을 인가하여 특정 형상을 갖고 있는 셀의 물리적 파괴여부를 판단할 수 있는 장치, 그리고 셀의 전해질에 내재된 결함을 검출할 수 있는 장치를 제작하였다. 본 장치들은 $1,000cm^2$급 평판형 셀까지 검수할 수 있도록 고안하여 양산시스템에 접목시킬 수 있도록 고안된 것이다. 본 장치들을 이용한 검수결과, 현재 $700cm^2$급 평판형 셀의 경우 최대 camber가 4mm 이하, 전해질의 He leak rate는 $5{\times}10^{-5}mbar.l/s.cm^2$ 이하라는 검수규격을 본 연구소에서 운전하는 스택에 1차적으로 적용하였으며 현재 검수규격의 신뢰성 및 강화를 위한 연구를 수행 중에 있다.