• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.415-417
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• 2013

기존 복근운동 관련 어플리케이션들은 윗몸일으키기에 한해 횟수를 세서 기록해 주는 앱들이 많이 개발 중이다. 윗몸일으키기가 대중화되어 있긴 하지만 자칫 복근이 아닌 허리힘으로 상체를 들어 올릴 때 부상의 위험이 크다. 또한 뒷머리를 손으로 당겨서 목이 과도하게 숙여지게 운동 할 때 목 디스크 유발에도 지장을 줄 수 있다. 따라서 본 논문에서는 손은 귀 옆에 데고 허리는 바닥에서 떨어지지 않게 허리 위 상체만 들어 올리는 크런치 운동을 측정하기 위하여 방향 센서에 의한 횟수를 기록하는 어플리케이션을 개발하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.121-123
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• 2003

웹 프록시의 처리량을 향상하고자 하는 시도로 Hummingbird가 제시되었다. 그러나 Hummingbird의 복구방식은 느리기 때문에 좀더 빠르게 웹 프록시 저장장치를 복구할 수 있는 방법이 필요하게 되었다. 본 연구에서는 빠른 복구를 위하여 디스크의 일부만 읽어서 복구할 수 있도록 메타 정보를 위한 공간을 할당하도록 하였다. 또한 메타 정보를 기록하는 비용을 줄이기 위해 윈도우를 사용한 메타 정보 관리 방식을 적용하여 윈도우 안에서만 클러스터를 할당\ulcorner삭제할 수 있도록 하며, 윈도우의 이동에 따라 메타 정보를 모아서 기록할 수 있도록 한다. 윈도우를 사용한 메타 정보 관리 방식에서는 윈도우에 포함된 클러스터들의 메타 정보만이 잘못될 수 있도록 하여 복구 시에 윈도우에 포함된 클러스터들의 메타 정보를 삭제하고 빠르게 복구할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.6 s.360
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• pp.28-33
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• 2007

The front-end system having a capable of 2x reading and writing of BD-R/Ra/ROM is developed. Its readability is improved by adopting 5-tap adaptive partial response maximum likelihood (PRML) with the PR(a,b,c,d,e) type channel. Due to the proposed PRML, less than $2{\times}10^{-4}$ of the bit error rate (BER) is achieved with radial and tangential tilt margin of over${\mp}0.6{\circ}$ on 25GB disc in 2x speed. The method of an optimum Power control (OPC) for stable writing of various BD-R/RE is proposed. The developed chip contains 14-million transistors in a $60mm^2$ dies, and is fabricated in $0.18-{\mu}m$ CMOS technology.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.371-376
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• 2000

For multi-hologram recording especially in a dIsk-shaped storage medium. we had studied a simple cost-effective method to unplement the rotational, angular, and ,patial multiplexmg techniques together in order to enhance the area storage density. Holographic storage with both rotational and angular multIplexing was realized by controlling the rderence beam directly with a pair of wedge prisms. whlie the storage WIth spatIal multlplexmg by shIfting the storage medium. In thIS paper \ve show that lhe area storage density of our system is strongly dependent on f numbers of the lenses in the srgnal and reference anns, and also show that the area storage densrly becollles maximal when the f number of the lens in the signal arm is approximately twice as long for a given f number of the lens in the reference emn. e emn.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.787-789
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• 2005

최근 이동성이 중요한 요소로 차지하는 기기들이 등장하면서 플래시 메모리가 각광을 받고 있다. 플래시 메모리의 소형화, 대용량화, 저전력화, 비휘발성, 고속화 그리고 충격에 강한 장점으로 인하여 많은 응용에서 디스크를 대체할 것으로 예상된다. 하지만 이런 플래시 메모리는 데이터를 기록하기 전에 해당 블록이 미리 소거가 되어야 하는 제약 조건을 가지고 있으며 각 블록들의 최대 소거 횟수가 제한되어 있다는 한계가 있다. 이때 소거 연산이 특정 블록에 집중되어 특정 블록의 수명이 단축되는 문제점을 해결하기 위하여 블록에 대한 소거 횟수 평준화 기법(wear-leveling)이 필요하다. 기존에 제안된 소거 횟수 평준화 기법은 각 블록의 소거 횟수를 유지해야하는 비용이 필요로 하거나 플래시 메모리가 대용량일 경우에는 블록 영역을 이동시키는데 비용이 발생하는 문제가 있다. 본 논문에서는 플래시 메모리의 소거 횟수 평준화를 위하여 해당 블록의 소거 횟수에 대한 정보의 유지의 부담을 줄이고 플래시 메모리의 대용량화 및 디스크 대체 시에 효율적인 소거 횟수 평준화 기법을 제안하고, 실험을 통하여 성능의 우수함을 보인다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.8
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• pp.1-8
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• 2000

We have achieved a high aspect ratio track-following microactuator (TFMA) which is capable of driving 0.3 ${\mu}m$ magnetic head for hard disk drive (HDD). it was fabricated on silicon on insulator (SOI) wafer with 20 ${\mu}m$ trick active silicon and 2 ${\mu}m$ thick thermally grown oxide and piggyback electrostatic principle was used for driving TFMA. The first vibration mode frequency of TFMA was 18.5 kHz which is enough for a recording density of higher than 10 Gb/in$^2$. Its displacement was 1.4 ${\mu}m$ when 15 V dc bias plus 15 V ac sinusoidal driving input was applied and its electrostatic force was 50 N. The fabricated actuator shows 7.51 dB of gain margin and 50.98$^{\circ}$ of phase margin for 2.21 kHz servo-bandwidth.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.4
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• pp.213-225
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• 2007

Flash memory is widely used as a storage device for potable equipments such as digital cameras, MP3 players and cellular phones because of its characteristics such as its large volume and nonvolatile feature, low power consumption, and good performance. However, a block in flash memories should be erased to write because of its hardware characteristic which is called as erase-before-write architecture. The erase operation is much slower than read or write operations. FTL is used to overcome this problem. We compared the performance of the existing FTL algorithms on Windows-based OS. We have developed a tool called FTL APAT in order to gather I/O patterns of the disk and analyze the performance of the FTL algorithms. It is the log buffer scheme with full associative sector translation(FAST) that the performance is best.

• Journal of Korea Spatial Information System Society
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• v.10 no.2
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• pp.1-12
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• 2008

Automatic semiconductor manufacture system generating transaction from 50,000 to 500,000 per a second needs storage management system processing very large data at once. A lot of storage management systems are researched for storing very large data. Existing storage management system is typical DBMS on a disk. It is difficult that the DBMS on a disk processes the 500,000 number of insert transaction per a second. So, the DBMS on main memory appeared to use memory. But it is difficultthat very large data stores into the DBMS on a memory because of limited amount of memory. In this paper we propose storage management system using insert transaction of a block unit that can process insert transaction over 50,000 and store data on low storage cost. A transaction of a block unit can decrease cost for a log and index per each tuple as transforming a transaction of a tuple unit to a block unit. Besides, the proposed system come cost to decompress all block of data because the information of each field be loss. To solve the problems, the proposed system generates the index of each compressed block to prevent reducing speed for searching. The proposed system can store very large data generated in semiconductor system and reduce storage cost.

• Korean Journal of Optics and Photonics
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• v.12 no.4
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• pp.339-344
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• 2001

We propose a method to represent binary data by modulating both the intensity and the phase of uniform plane waves with a twisted-nematic liquid crystal display for holographic digital data storage especially in a disk-shaped recording medium. As far as intensity modulation is concerned, our method is not different from the conventional method, because binary bit values 0 and 1 are represented by the dark (off) and lit (on) states of the liquid crystal display pixels, respectively (or vice versa). With our method, however, the on pixels are also controlled so that the beams passing through them can have one of two different phase delays. If the difference of the two phase delays is close to 180 degrees, we can reduce the dc component of the data image and thus improve the beam intensity uniformity at the holographic recording plane when Fourier plane holograms are recorded. The feasibility of our method is experimentally demonstrated. rated.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.27 no.5
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• pp.1013-1022
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• 2017

Windows hibernation is a function that stores data of physical memory on a non-volatile media and then restores the memory data from the non-volatile media to the physical memory when the system is powered on. Since the hibernation file has memory data in a static state, when the attacker collects it, key information in the system's physical memory may be leaked. Because Windows does not support protection for hibernation files only, we need to protect the memory that is written to the hibernate file. In this paper, we propose a method to encrypt the physical memory data in the hibernation file to protect the memory data of the processes recorded in the hibernation file. Hibernating procedure is analyzed to encrypt the memory data at the hibernating and the encryption process for hibernation memory is implemented to operate transparently for each process. Experimental results show that the hibernation process memory encryption tool showed about 2.7 times overhead due to the crypt cost. This overhead is necessary to prevent the attacker from exposing the plaintext memory data of the process.