• Title/Summary/Keyword: 파일 복구

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A Branch Misprediction Recovery Mechanism by Control Independence (제어 독립성과 분기예측 실패 복구 메커니즘)

  • Ko, Kwang-Hyun;Cho, Young-Il
    • Journal of Practical Agriculture & Fisheries Research
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    • v.14 no.1
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    • pp.3-22
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    • 2012
  • Control independence has been put forward as a significant new source of instruction-level parallelism for superscalar processors. In branch prediction mechanisms, all instructions after a mispredicted branch have to be squashed and then instructions of a correct path have to be re-fetched and re-executed. This paper presents a new branch misprediction recovery mechanism to reduce the number of instructions squashed on a misprediction. Detection of control independent instructions is accomplished with the help of the static method using a profiling and the dynamic method using a control flow of program sequences. We show that the suggested branch misprediction recovery mechanism improves the performance by 2~7% on a 4-issue processor, by 4~15% on an 8-issue processor and by 8~28% on a 16-issue processor.

Implementation of Software Downloading and Installing for upgrading Digital TV Settop Box (디지털 방송 TV수신기의 기능 업그레이드를 위한 소프트웨어 다운로드와 설치 기능 구현)

  • Ryu Yll-Kwon;Jung Moon-Ryul;Kim Jung-Hwan;Choi Jin-Su;Bang Gun
    • Journal of Broadcast Engineering
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    • v.11 no.1 s.30
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    • pp.66-79
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    • 2006
  • As constant development of digital broadcasting and data broadcasting system, new technology will be introduced to digital broadcasting and new broadcasting service will be appeared. These services need to be changed and processed to suit each services and the software of the receiver need to be upgraded. Though, generally the digital broadcasting receivers are not getting updated once it's delivered to home for long time and it need to be done by hand or collected each one of them with trouble. Therefore this paper suggests a way to overcome these difficulties via broadcasting stream. This research is to describe how three modules-namely (1) Downloader, downloads new software from data carrousel stream, (2) Update Loader, installs the software received by downloader; and (3) Recoverer, recovers the former version of the software if some serious problem has been occurred during downloading and installing the software. This paper tries to realize the accommodation of terrestrial STB based on the new technique and service following ATSC A-97 agreement.

Deriving Priorities of Competences Required for Digital Forensic Experts using AHP (AHP 방법을 활용한 디지털포렌식 전문가 역량의 우선순위 도출)

  • Yun, Haejung;Lee, Seung Yong;Lee, Choong C.
    • The Journal of Society for e-Business Studies
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    • v.22 no.1
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    • pp.107-122
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    • 2017
  • Nowadays, digital forensic experts are not only computer experts who restore and find deleted files, but also general experts who posses various capabilities including knowledge about processes/laws, communication skills, and ethics. However, there have been few studies about qualifications or competencies required for digital forensic experts comparing with their importance. Therefore, in this study, AHP questionnaires were distributed to digital forensic experts and analyzed to derive priorities of competencies; the first-tier questions which consisted of knowledge, technology, and attitude, and the second-tier ones which have 20 items. Research findings showed that the most important competency was knowledge, followed by technology and attitude but no significant difference was found. Among 20 items of the second-tier competencies, the most important competency was "digital forensics equipment/tool program utilization skill" and it was followed by "data extraction and imaging skill from storage devices." Attitude such as "judgment," "morality," "communication skill," "concentration" were subsequently followed. The least critical one was "substantial law related to actual cases." Previous studies on training/education for digital forensics experts focused on law, IT knowledge, and usage of analytic tools while attitude-related competencies have not given proper attention. We hope this study can provide helpful implications to design curriculum and qualifying exam to foster digital forensic experts.

A Study On Artifacts Analysis In Portable Software (무 설치 프로그램에서의 사용자 행위 아티팩트 분석)

  • Taeyeong Heo;Taeshik Shon
    • Journal of Platform Technology
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    • v.11 no.2
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    • pp.39-53
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    • 2023
  • Non-installation program (hereinafter referred to as "portable program") is a program that can be used without an installation process, unlike general software. Since there is no separate installation process, portable programs have high mobility and are used in various ways. For example, when initial setup of multiple PCs is required, a portable program can be stored on one USB drive to perform initial setup. Alternatively, when a problem occurs with the PC and it is difficult to boot normally, Windows PE can be configured on the USB drive and portable programs can be stored for PC recovery. And the portable program does not directly affect PC settings, such as changing registry values, and does not leave a trace. This means that the portable program has high security. If a portable program is deleted after using it, it is difficult to analyze behavior in a general way. If a user used a portable program for malicious behavior, analysis in a general way has limitations in collecting evidence. Therefore, portable programs must have a new way of behavioral analysis that is different from ordinary installation software. In this paper, after installing the Windows 10 operating system on a virtual machine, we proceed with the scenario with a portable program of Opera and Notepad++. And we analyze this in various ways such as file analysis of the operating system and memory forensics, collect information such as program execution time and frequency, and conduct specific behavioral analysis of user.

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Application of Terrestrial LiDAR for Reconstructing 3D Images of Fault Trench Sites and Web-based Visualization Platform for Large Point Clouds (지상 라이다를 활용한 트렌치 단층 단면 3차원 영상 생성과 웹 기반 대용량 점군 자료 가시화 플랫폼 활용 사례)

  • Lee, Byung Woo;Kim, Seung-Sep
    • Economic and Environmental Geology
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    • v.54 no.2
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    • pp.177-186
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    • 2021
  • For disaster management and mitigation of earthquakes in Korea Peninsula, active fault investigation has been conducted for the past 5 years. In particular, investigation of sediment-covered active faults integrates geomorphological analysis on airborne LiDAR data, surface geological survey, and geophysical exploration, and unearths subsurface active faults by trench survey. However, the fault traces revealed by trench surveys are only available for investigation during a limited time and restored to the previous condition. Thus, the geological data describing the fault trench sites remain as the qualitative data in terms of research articles and reports. To extend the limitations due to temporal nature of geological studies, we utilized a terrestrial LiDAR to produce 3D point clouds for the fault trench sites and restored them in a digital space. The terrestrial LiDAR scanning was conducted at two trench sites located near the Yangsan Fault and acquired amplitude and reflectance from the surveyed area as well as color information by combining photogrammetry with the LiDAR system. The scanned data were merged to form the 3D point clouds having the average geometric error of 0.003 m, which exhibited the sufficient accuracy to restore the details of the surveyed trench sites. However, we found more post-processing on the scanned data would be necessary because the amplitudes and reflectances of the point clouds varied depending on the scan positions and the colors of the trench surfaces were captured differently depending on the light exposures available at the time. Such point clouds are pretty large in size and visualized through a limited set of softwares, which limits data sharing among researchers. As an alternative, we suggested Potree, an open-source web-based platform, to visualize the point clouds of the trench sites. In this study, as a result, we identified that terrestrial LiDAR data can be practical to increase reproducibility of geological field studies and easily accessible by researchers and students in Earth Sciences.