• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.737-740
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• 2007

기존의 백업시스템에서는 데이터의 중복을 고려하지 않고 백업 데이터 전부를 저장하기 때문에 저장용량 공간을 많이 차지하는 문제점이 있다. 본 논문에서는 이러한 문제점을 해결하기 위해 백업 데이터의 각 파일에 대해서 일정한 크기의 블록 단위로 파일지문을 부여하고 파일지문이 동일할 경우 하나의 사본만을 공유하는 방법으로 백업 데이터의 용량을 감소시키는 방법을 도입하였다. 제안하는 백업 시스템은 중복되어 발생하는 데이터에 대해 하나의 사본만 백업함으로써 백업되는 데이터의 양을 효과적으로 감소시켰다. 또한 백업되는 파일 블록에 대해서 클러스터링 기술을 사용함으로서 입출력 성능 향상을 고려하였다.

• Journal of KIISE
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• v.42 no.4
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• pp.427-433
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• 2015

The rapid advancement of computing technology has triggered the need for fast data I/O processing and high-performance storage technology. Next generation memory technology, which we refer to as new memory, is anticipated to be used for high-performance storage as they have excellent characteristics as a storage device with non-volatility and latency close to DRAM. This research proposes NTL (New memory Translation layer) as a technology to make use of new memory as storage. With the addition of NTL, conventional I/O is served with existing mature disk-based file systems providing compatibility, while new memory I/O is serviced through the NTL to take advantage of the byte-addressability feature of new memory. In this paper, we describe the design of NTL and provide experiment measurement results that show that our design will bring performance benefits.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.324-336
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• 2000

The paper proposes an efficient buffer management scheme to enhance performance of the disk I/O system. Without any user level information, the proposed scheme automatically detects the block reference patterns of applications by associating block attributes with forward distance of a block. Based on the detected patterns, the scheme applies an appropriate replacement policy to each application. We also present a new block allocation scheme to improve the performance of buffer cache when kernel needs to allocate a cache block due to a cache miss. The allocation scheme analyzes the cache hit ratio of each application based on block reference patterns and allocates a cache block to maximize cache hit ratios of system. These all procedures are performed on-line, as well as automatically at system level. We evaluate the scheme by trace-driven simulation. Experimental results show that our scheme leads to significant improvements in hit ratios of cache blocks compared to the traditional schemes and requires low overhead.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.1-14
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• 2020

In this paper, we propose to solve the problem of increasing system memory usage due to an increase in the number of mapping information management when using a NAND flash memory-based storage device in an existing sector-based file system. The proposed technique is to store only mapping information in page units based on index blocks and manage them in block units. To this end, the proposed technique uses a sequential offset for storing and managing a plurality of mapping information in one page in a small block, and a reverse offset for a spare page corresponding to a change in mapping information in the block. Through this, the proposed technique has the advantage that the number of block-unit deletions is less than that of the existing technique, and the system memory usage required for mapping information management is low. Reduced by about 32%.

• Proceedings of The KACE
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• 2018.08a
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• pp.63-66
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• 2018

초, 중, 고 정규 교육과정에 피지컬컴퓨팅 단원이 포함 되었고 교구 지향적인 특성을 갖는다. 피지컬 단원을 위해 매우 다양한 교구가 출시 되고 있으나 학생들의 창의적인 아이디어를 모두 수용 가능하며 저렴한 교구는 찾기 힘들다. 저렴하고 막강한 기능을 가진 아두이노가 최적의 보드이지만 어려운 하드웨어 세팅과 텍스트 코딩 기반이라 외면 받고 있다. 또한 블록코딩이 가능하긴 하나 단순한 디지털, 아날로그 센서 제어 명령만 제공하다 보니 다른 보드와 기능적인 차이는 없으면서 하드웨어 세팅만 어렵게 느껴진다. 아두이노가 가진 다양한 입, 출력 모듈을 제한 없이 사용 가능한 장점을 훼손하지 않으며, 코딩이 쉬우려면 센서 제한 없는 블록코딩이 되어야 한다. 만약 아두이노가 하드웨어 세팅이 쉬우면서 거의 모든 입출력장치를 블록명령으로 제어가능하다면 초중고 학생들이 자신의 아이디어를 제한 없이 구현하여 창의적인 작품을 만들 수 있을 것이다. 따라서 블록코딩으로 아두이노의 막강한 기능을 제한 없이 사용하기 위한 방법을 연구하고, 해결책을 찾아 제시한다.

• Journal of Broadcast Engineering
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• v.24 no.6
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• pp.956-964
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• 2019

In the age of personal media such as YouTube and Twitch, individual media content creation and consumption have become simpler. A huge amount of media content is created and consumed through platform services. In this regard, interest in copyright of media contents is increasing. In particular, the sound source is an indispensable element in almost all media contents production. In this paper, we propose a method to store the sound source and its signature using blockchain and distributed storage system to verify the copyright of music contents. We Identify the possibility of including the audio signature extraction result of the sound source as blockchain transaction data. Through experiments, we compare the input and output speed when the sound source and its signature are stored in the distributed storage system.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.107-115
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• 2014

The reduced-bit transform based bit-plane matching algorithm (BPM) can obtain the block matching result through its simple calculation and hardware design compared to the conventional block matching algorithms (BMAs), but the block matching accuracy of BPMs is somewhat low. In this paper, reduced-bit transform based sum of the absolute difference (R-SAD) is proposed to improve the block matching accuracy in comparison with the conventional BPMs and it is shown that the matching process can be obtained using the logical operations. Firstly, this method transforms the current and the reference images into their respective 2-bit images and then a truth table is obtained from the relation between input and output 2-bit images. Next, a truth table is simplified by Karnaugh map and the absolute difference is calculated by using simple logical operations. Finally, the simulation results show that the proposed R-SAD can obtain higher accuracy in block matching results compared to the conventional BPMs through the PSNR analysis in the motion compensation experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.493-497
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• 2005

This paper is about the research of the User Agent implementation under wireless embedded environment, using SIP which is one of protocol components construct the VoIP system. The User Agent is made of the User Agent configuration block, the device thread block to control devices and the SIP stack block to process SIP messages. The device thread consists of the RTP thread and the sound lard device processing block. Futhermore, the SIP stack consist of the worker thread to process proxy events, the SIP transceiver and SIP thread to transfer and receive SIP messages. The H/W platform is a board included the Intel's XScale PXA255 processor, flash memory, SDRAM, Audio CODEC module and wireless LAN threough PCMCIA socket, furthermore a microphone and headphone is used by the audio 1/0. The system has embedded linux kernel 2.4.19. For embedded environment, the function of User Agent and SIP method is diminished. Finally, the resource of system could be reduced about $12.9\%$, compared to overall system resource, by minimizing peripherals control and excepting TCP.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.8
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• pp.12-18
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• 2012

In this paper, we propose an improved analysis of transmission power of BTHP applied into the downlink multi-user (MU) multi-input multi-output (MIMO) system. On the contrary to the conventional analysis that adopts the strong interference assumption for every users in the system, the proposed analysis approximates the characteristics of the actual interference components so that provides more accurate approximation of the transmission power than that from the conventional analysis. By computer simulations, it is observed that the proposed approximation is more accurate than the conventional one, especially in the case of 4-QAM modulation.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.91-95
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• 2008

Flash memory is widely used in embedded systems because of its benefits such as non-volatile, shock resistant, and low power consumption. But NAND flash memory suffers from out-place-update, limited erase cycles, and page based read/write operations. To solve these problems, log-structured filesystem was proposed such as YAFFS. However, YAFFS sequentially retrieves an array of all block information to allocate free block for a write operation. Also before the write operation, YAFPS read the array of block information to find invalid block for erase. These could reduce the performance of the filesystem. This paper suggests fast operation method for NAND flash filesystem that solves the above-mentioned problems. We implemented the proposed methods in YAFFS. And we measured the performance compared with the original technique.