• Title/Summary/Keyword: Storage Speed

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Cross Compressed Replication Scheme for Large-Volume Column Storages (대용량 컬럼 저장소를 위한 교차 압축 이중화 기법)

  • Byun, Siwoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.5
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    • pp.2449-2456
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    • 2013
  • The column-oriented database storage is a very advanced model for large-volume data analysis systems because of its superior I/O performance. Traditional data storages exploit row-oriented storage where the attributes of a record are placed contiguously in hard disk for fast write operations. However, for search-mostly datawarehouse systems, column-oriented storage has become a more proper model because of its superior read performance. Recently, solid state drive using MLC flash memory is largely recognized as the preferred storage media for high-speed data analysis systems. In this paper, we introduce fast column-oriented data storage model and then propose a new storage management scheme using a cross compressed replication for the high-speed column-oriented datawarehouse system. Our storage management scheme which is based on two MLC SSD achieves superior performance and reliability by the cross replication of the uncompressed segment and the compressed segment under high workloads of CPU and I/O. Based on the results of the performance evaluation, we conclude that our storage management scheme outperforms the traditional scheme in the respect of update throughput and response time of the column segments.

Large Storage Performance and Optimization Study using blockwrite (blockwrite를 이용한 대형 스토리지 성능 측정 및 최적화 연구)

  • Kim, Hyo-Ryoung;Song, Min-Gyu;Kang, Yong-Woo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.6
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    • pp.1145-1152
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    • 2021
  • In order to optimize the performance of 1.4P large storage, the characteristics of each chunk mode were investigated, and the chunk 512K mode was selected in terms of I/O speed. NVME storage system was configured and used to measure data server performance of large storage. By measuring the change in throughput according to the number of threads of the 1.4P large storage, the characteristics of the large storage system were identified, and it was confirmed that the performance was up to 133Gbps with a block size of 32KB. As a result of data transmission/reception experiment using globus-url-copy of GridFTP, it was found that this large storage has a throughput of 33Gbps.

An Experimental Investigation on Effects of Gas Hydrate Formation Factors For NGH Transport Technology Development (NGH 수송기술 개발을 위한 주요 인자별 제조특성 실험 연구)

  • Kim, You-Na;Shin, Chang-Hoon;Han, Jeong-Min;Shin, Kwang-Sik;Kim, Byoung-Joo;Lee, Jeong-Hwan
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.511-514
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    • 2007
  • Gas hydrate has a unique property that can store a large volume of gas in water as a solid form. Even though investigations for natural gas storage technology have been carried out for several decades, there are still a lot of unsolved problems due to complex formation process, low formation speed, high energy consumption and so on. So, lots of experiments were conducted to overcome these weaknesses and to develop artificial NGH formation technology applicable to industrial-scale storage and commercial transport. In this study, some series of experiments were performed to analyze both stirred and unstirred system especially about the influences of several gas hydrate formation factors such as agitation speed, system temperature, SDS concentration, etc. As a result, optimum range of SDS concentration and temperature that could enhance the storage capacity and shorten the formation time were found. And it is obviously presented that SDS such a kind of surfactant promotes gas hydrate formation dramatically and the quantity of stored gas are proportional to agitation speed in stirred system.

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Modeling and Position-Sensorless Control of a Dual-Airgap Axial Flux Permanent Magnet Machine for Flywheel Energy Storage Systems

  • Nguyen, Trong Duy;Beng, Gilbert Foo Hock;Tseng, King-Jet;Vilathgamuwa, Don Mahinda;Zhang, Xinan
    • Journal of Power Electronics
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    • v.12 no.5
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    • pp.758-768
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    • 2012
  • This paper presents the modeling and position-sensorless vector control of a dual-airgap axial flux permanent magnet (AFPM) machine optimized for use in flywheel energy storage system (FESS) applications. The proposed AFPM machine has two sets of three-phase stator windings but requires only a single power converter to control both the electromagnetic torque and the axial levitation force. The proper controllability of the latter is crucial as it can be utilized to minimize the vertical bearing stress to improve the efficiency of the FESS. The method for controlling both the speed and axial displacement of the machine is discussed. An inherent speed sensorless observer is also proposed for speed estimation. The proposed observer eliminates the rotary encoder, which in turn reduces the overall weight and cost of the system while improving its reliability. The effectiveness of the proposed control scheme has been verified by simulations and experiments on a prototype machine.

Sizing and Economic Analysis of Battery Energy Storage System for Peak Shaving of High-Speed Railway Substations (고속철도 변전소 피크부하 저감용 ESS 용량 산정 및 경제성 분석)

  • Kim, Seul-Ki;Kim, Jong-Yul;Cho, Kyeong-Hee;Byun, Gil-Sung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.1
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    • pp.27-34
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    • 2014
  • The paper proposed a sizing method of an energy storage system(ESS) for peak shaving of high-speed railway substations based on load profile patterns of substations. A lithium based battery ESS was selected since it can produce high-power at high speed that peak shaving requires, and also takes up a relatively smaller space for installation. Adequate size of the ESS, minimum capacity which can technically meet a peak shaving target, was determined by collectively considering load patterns of a target substation, characteristics of the ESS to be installed, and optimal scheduling of the ESS. In case study, a local substation was considered to demonstrate the proposed sizing method. Also economic analysis with the determined size of ESS was performed to calculate electricity cost savings of the peak shaving ESS, and to offer pay-back period and return on investment.

Implementation of Hardware RAID and LVM-based Large Volume Storage on Global Data Center System of International GNSS Service

  • Lee, Dae-Kyu;Cho, Sung-Ki;Park, Jong-Uk;Park, Pil-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1553-1557
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    • 2005
  • High performance and reliability of the storage system to handle a very large amount of data has been become very important. Many techniques have been applied on the various application systems to establish very large capacity storage that satisfy the requirement of high I/O speed and physical or logical failure protection. We applied RAID and LVM to construct a storage system for the global data center which needs a very reliable large capacity storage system. The storage system is successfully established and equipped on the latest Linux application server.

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Mirror-Switching Scheme for High-Speed Embedded Storage Systems (고속 임베디드 저장 시스템을 위한 복제전환 기법)

  • Byun, Si-Woo;Jang, Seok-Woo
    • Transactions of the Society of Information Storage Systems
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    • v.7 no.1
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    • pp.7-12
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    • 2011
  • The flash memory has been remarked as the next generation media of portable and desktop computers' storage devices. Their features include non-volatility, low power consumption, and fast access time for read operations, which are sufficient to present flash memories as major data storage components for desktop and servers. The purpose of our study is to upgrade a traditional mirroring scheme based on SSD storages due to the relatively slow or freezing characteristics of write operations, as compared to fast read operations. For this work, we propose a new storage management scheme called Memory Mirror-Switching based on traditional mirroring scheme. Our Mirror-Switching scheme improves flash operation performance by switching write-workloads from flash memory to RAM and delaying write operations to avoid freezing. Our test results show that our scheme significantly reduces the write operation delay and storage freezing.

Changes of Physical and Sensory Quality in Home-delivered meals for elderly as affected by Packaging methods and Storage conditions 3 (노인을 위한 가정배달급식의 포장방법 및 저장조건에 따른 물성ㆍ관능적 품질 변화 3)

  • 김혜영;류시현
    • Korean journal of food and cookery science
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    • v.19 no.3
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    • pp.374-389
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    • 2003
  • The Purpose of this study was to propose the most effective packaging method and storage conditions to apply to home-delivered meals for the elderly Changes in the physical and sensory qualities of pan fried oak mushroom and meat, soy sauce glazed hair tail and roasted dodok, in wrap packaging, top sealing and vacuum packaging were evaluated during storage at 25, 4 and -18$^{\circ}C$, for 5 days. The speed of falling-off in the foods qualities, under chilled and frozen storage conditions did not differ much as the 5 day storage period was too short for a proper assessment. The sensory characteristics of taste and texture were better evaluated in the chilled than in the frozen storage. The most effective packaging method at all the storage temperatures was the vacuum packaging, which assured the safety of the foods by the removal of oxygen. The lightness, springiness and hardness were significantly influenced by the storage temperature, period and packaging method, while the sensory characters were affected by storage temperature and the period. In conclusion, the quality of the vacuum packed pan fried oak mushroom and meat and soy sauce glazed hair tail, in frozen storage, were still fresh after the five days of the experiment. The shelf-life of those foods with wrap packaging, in chilled storage, were suggested to be three days. The quality of the roasted dodok, with vacuum packaging in chilled storage, was preserved for five days.

Hardware Implementation of High Speed CODEC for PACS (PACS를 위한 고속 CODEC의 하드웨어 구현)

  • 유선국;박성욱
    • Journal of Biomedical Engineering Research
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    • v.15 no.4
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    • pp.475-480
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    • 1994
  • For the effective management of medical images, it becomes popular to use computing machines in medical practice, namely PACS. However, the amount of image data is so large that there is a lack of storage space. We usually use data compression techniques to save storage, but the process speed of machines is not fast enough to meet surgical requirement. So a special hardware system processing medical images faster is more important than ever. To meet the demand for high speed image processing, especially image compression and decompression, we designed and implemented the medical image CODEC (COder/DECoder) based on MISD (Multiple Instruction Single Data stream) architecture to adopt parallelism in it. Considering not being a standard scheme of medical image compression/decompression, the CODEC is designed programable and general. In this paper, we use JPEG (Joint Photographic Experts Group) algorithm to process images and evalutate the CODEC.

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Frequency control of flywheel energy storage system based on a variable gain depending on the rotor speed and frequency deviation (회전자 속도와 주파수 편차에 따라 변하는 가변게인을 이용한 플라이휠 에너지 저장장치의 주파수 제어)

  • Lee, Hyewon;Na, Woonki;Kim, Jonghoon
    • Proceedings of the KIPE Conference
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    • 2018.07a
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    • pp.354-355
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    • 2018
  • Flywheel energy storage system (FESS) operates motor or generator by utilizing the stored kinetic energy in the rotating mass. Thus, the FESS can support the frequency control of the power system. However, the FESS is disabled when the rotor speed reaches to its minium value. Thus, the second frequency dip occurs in the power system. This paper proposes the frequency control scheme of FESS based on a variable gain depending on the rotor speed and frequency deviation. The proposed scheme prevents the second frequency dip because the variable gain decreases depending on the stored in the FESS. The performance of the proposed scheme is investigated for the IEEE 14-bus system.

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