• Title/Summary/Keyword: Memory access

Search Result 1,134, Processing Time 0.054 seconds

Standardizing Digitization for Preservation and Access to Rare Library Materials (도서관 희귀 자료의 보존과 접근을 위한 디지털화의 표준화)

  • Knoll, Adolf
    • Journal of Korean Society of Archives and Records Management
    • /
    • v.5 no.2
    • /
    • pp.167-182
    • /
    • 2005
  • The beginning of digitization activities in the National Library of the Czech Republic are interconnected with the first periods of existence of the UNESCO Memory of the World programme. It was in 1992 when the library accepted the UNESCO proposal to prepare a pilot CD ROM publication for the programme showing the most precious items from its collections. In 1993 - 1995, the publication was followed by two another titles, which presented two medieval manuscripts in their entirety, providing both all the image documentation and scientific description of various features of the original documents. The digitization centre specialized in processing of old manuscripts and old printed books in co operation with the Czech AIP Beroun Company. Nowadays, these two national programmes in which dozens of Czech and also several foreign institutions take part - are represented on their access side by two digital libraries: Manuscriptorium and Kramerius.

A Streaming XML Parser Supporting Adaptive Parallel Search (적응적 병렬 검색을 지원하는 스트리밍 XML 파서)

  • Lee, Kyu-Hee;Han, Sang-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.17 no.8
    • /
    • pp.1851-1856
    • /
    • 2013
  • An XML is widely used for web services, such as SOAP(Simple Object Access Protocol) and REST (Representational State Transfer), and also de facto standard for representing data. Since the XML parser using DOM(Document Object Model) requires a preprocessing task creating a DOM-tree, and then storing it into memory, embedded systems with limited resources typically employ a streaming XML parser without preprocessing. In this paper, we propose a new architecture for the streaming XML parser using an APSearch(Adaptive Parallel Search) on FPGA(Field Programmable Gate Array). Compared to other approaches, the proposed APSearch parser dramatically reduces overhead on the software side and achieves about 2.55 and 2.96 times improvement in the time needed for an XML parsing. Therefore, our APSearch parser is suitable for systems to speed up XML parsing.

Block Device Driver of Linux for Accessing the NRD (NRD 접근을 위한 리눅스 블록 디바이스 드라이버)

  • Son, Tae-Yeong;Rim, Seong-Rak
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.16 no.5
    • /
    • pp.3399-3406
    • /
    • 2015
  • NRD(Network RamDisk) is a scheme which allows a system to use the memory of the remote systems just as his own block device via networking. Basically, it consists of a client requesting an NRD access and server providing the NRD. In this paper, we describe the design, implementation and experiment of the block device driver for accessing the NRD in the Linux kernel(2.6) level. First of all, we have analyzed the flow of processing the requests for accessing the block devices in the traditional Linux kernel and figured out the additional functions required for supporting the NRD. Then we have designed and implemented the device diver of NRD client and NRD server for providing these functions. Finally, we have established a NRD server system, and reviewed its functional feasibility by experimenting the requests of NRD access through the NRD device driver implemented on a NRD client.

PRMS: Page Reallocation Method for SSDs (PRMS: SSDs에서의 Page 재배치 방법)

  • Lee, Dong-Hyun;Roh, Hong-Chan;Park, Sang-Hyun
    • The KIPS Transactions:PartD
    • /
    • v.17D no.6
    • /
    • pp.395-404
    • /
    • 2010
  • Solid-State Disks (SSDs) have been currently considered as a promising candidate to replace hard disks, due to their significantly short access time, low power consumption, and shock resistance. SSDs, however, have drawbacks such that their write throughput and life span are decreased by random-writes, nearly regardless of SSDs controller designs. Previous studies have mostly focused on better designs of SSDs controller and reducing the number of write operations to SSDs. We suggest another method that reallocates data pages that tend to be simultaneously written to contiguous blocks. Our method gathers write operations during a period of time and generates write traces. After transforming each trace to a set of transactions, our method mines frequent itemsets from the transactions and reallocates the pages of the frequent itemsets. In addition, we introduce an algorithm that reallocates the pages of the frequent itemsets with moderate time complexity. Experiments using TPC-C workload demonstrated that our method successfully reduce 6% of total logical block access.

Design and Implementation of Multimedia Mobile Learning System using MSMIL (MSMIL을 이용한 멀티미디어 모바일 학습시스템의 설계 및 구현)

  • Lim, Young-Jin;Seo, Jung-Hee;Park, Hung-Bog
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.11 no.3
    • /
    • pp.592-599
    • /
    • 2007
  • The advancement of wireless technology improves the electronic learning by combining with the mobile function, and promotes the expanded transition to the mobile learning. Basically, the mobile learning provides the usefulness in terms of tile and space to provide learners with the access to the educational contents. However, the small display device and limited memory space of mobile device is limiting the access to the learning contents simply to the text-based transmission. This paper designed and implemented the multimedia mobile learning system that reduces the size of parser by define into MSMIL composed only of needed tag to multimedia contents production in the mobile devices by using the SMIL that supports the multimedia object synchronization reduces the data of multimedia learning data and enhances the transmission efficiency by applying the macro method in creating the contents of learning. The results of implementation indicates that it simplifies the designing language, makes the language learning easy, and saves the CPU resources for the parsing by reducing the size of parser.

Vulnerability Analysis Method of Software-based Secure USB (소프트웨어 기반 보안 USB에 대한 취약성 분석 방법론)

  • Kim, Minho;Hwang, Hyunuk;Kim, Kibom;Chang, Taejoo;Kim, Minsu;Noh, Bongnam
    • Journal of the Korea Institute of Information Security & Cryptology
    • /
    • v.22 no.6
    • /
    • pp.1345-1354
    • /
    • 2012
  • The modern society with the wide spread USB memory, witnesses the acceleration in the development of USB products that applied secure technology. Secure USB is protecting the data using the method as device-based access control, encryption of stored files, and etc. In terms of forensic analyst, to access the data is a lot of troubles. In this paper, we studied software-based data en/decryption technology and proposed for analysis mechanism to validation vulnerability that secured on removable storage media. We performed a vulnerability analysis for USB storage device that applied security mechanism. As a result, we found vulnerabilities that extracts a source file without a password.

VDI deployment and performance analysys for multi-core-based applications (멀티코어 기반 어플리케이션 운용을 위한 데스크탑 가상화 구성 및 성능 분석)

  • Park, Junyong
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.26 no.10
    • /
    • pp.1432-1440
    • /
    • 2022
  • Recently, as Virtual Desktop Infrastructure(VDI) is widely used not only in office work environments but also in workloads that use high-spec multi-core-based applications, the requirements for real-time and stability of VDI are increasing. Accordingly, the display protocol used for remote access in VDI and performance optimization of virtual machines have also become more important. In this paper, we propose two ways to configure desktop virtualization for multi-core-based application operation. First, we propose a codec configuration of a display protocol with optimal performance in a high load situation due to multi-processing. Second, we propose a virtual CPU scheduling optimization method to reduce scheduling delay in case of CPU contention between virtual machines. As a result of the test, it was confirmed that the H.264 codec of Blast Extreme showed the best and stable frame, and the scheduling performance of the virtual CPU was improved through scheduling optimization.

An Active Prefetch Filtering Schemes using Exclusive Prefetch Cache (선인출 전용 캐시를 이용한 적극적 선인출 필터링 기법)

  • Chon Young-Suk;Kim Suk-il;Jeon Joong-nam
    • The KIPS Transactions:PartA
    • /
    • v.12A no.1 s.91
    • /
    • pp.41-52
    • /
    • 2005
  • Memory reference instruction caused by cache miss is the critical factor that limits the processing power of processor. Cache prefetching technique is an effective way to reduce the latency due to memory access. However, excessively aggressive prefetch leads to cache pollution and finally to cancel out the advantage of prefetch. In this study, an active prefetch filtering scheme is introduced which dynamically decides whether to commence prefetching after referring a filtering table to reduce the cache pollution due to unnecessary prefetches. For the precision filtering, an evicted address referencing scheme has been proposed where the filter directly compares the current prefetch address with previous unnecessary prefetch addresses stored in filtering table. Moreover, a small sized exclusive prefetch cache has been introduced to increase the amount of eviction of unnecessarily prefetched addresses to enhance the accuracy of dynamic filtering. The exclusive prefetch cache also prevents useful demand data from being pushed out by prefetched data, while the evicted address direct referencing scheme enables the prefetch cache to keep most of useful prefetch data within its small size. Experimental results from commonly used general and multimedia benchmarks show that the average cache miss ratio has been decreased by $13.3{\%}$ by virtue of enhanced filtering accuracy compared with conventional schemes.

Dynamic Prefetch Filtering Schemes to enhance Utilization of Data Cache (데이타 캐시의 활용도를 높이는 동적 선인출 필터링 기법)

  • Chon, Young-Suk;Kim, Suk-Il;Jeon, Joong-Nam
    • Journal of KIISE:Computer Systems and Theory
    • /
    • v.35 no.1
    • /
    • pp.30-43
    • /
    • 2008
  • Memory reference instructions such as loads or stores are critical factors that limit the processing power of processor. The prefetching technique is an effective way to reduce the latency caused from memory access. However, excessively aggressive prefetch leads to cache pollution so as to cancel out the advantage of prefetch. In this study, four filtering schemes have been compared and evaluated which dynamically decide whether to begin prefetch after referring a filtering table to decrease cache pollution. First, A bi-states scheme has been shown to analyze the lock problem of the conventional scheme, this scheme such as conventional scheme used to be N:1 mapping, but it has the two state to 1bit value of each entries. A complete state scheme has been introduced to be used as a reference for the comparative study. A block address lookup scheme has been proposed as the main idea of this paper which exhibits the most exact filtering performance. This scheme has a length of the table the same as the bi-states scheme, the contents of each entry have the fields the same as the complete state scheme recently, never referenced data block address has been 1:1 mapping a entry of the filter table. Experimental results from commonly used general benchmarks and multimedia programs show that average cache miss ratio have been decreased by 10.5% for the block address lookup scheme(BAL) compare to conventional dynamic filter scheme(2-bitSC).

Microstructure and Electrical Properties of the Pt/Pb1.1Zr0.53Ti0.47O3/PbO/Si (MFIS) Using the PbO Buffer Layer (PbO 완충층을 이용한 Pt/Pb1.1Zr0.53Ti0.47O3/PbO/Si (MFIS)의 미세구조와 전기적 특성)

  • Park, Chul-Ho;Song, Kyoung-Hwan;Son, Young-Guk
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.2 s.273
    • /
    • pp.104-109
    • /
    • 2005
  • To study the role of PbO as the buffer layer, Pt/PZT/PbO/Si with the MFIS structure was deposited on the p-type (100) Si substrate by the r.f. magnetron sputtering with $Pb_{1.1}Zr_{0.53}Ti_{0.47}O_3$ and PbO targets. When PbO buffer layer was inserted between the PZT thin film and the Si substrate, the crystallization of the PZT thin films was considerably improved and the processing temperature was lowered. From the result of an X-ray Photoelectron Spectroscopy (XPS) depth profile result, we could confirm that the substrate temperature for the layer of PbO affects the chemical states of the interface between the PbO buffer layer and the Si substrate, which results in the inter-diffusion of Pb. The MFIS with the PbO buffer layer show the improved electric properties including the high memory window and low leakage current density. In particular, the maximum value of the memory window is 2.0V under the applied voltage of 9V for the Pt/PZT(200 nm, $400^{\circ}C)/PbO(80 nm)/Si$ structures with the PbO buffer layer deposited at the substrate temperature of $300^{\circ}C$.