• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.3
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• pp.79-91
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• 2010

In digital forensics, the creation time, last modified time, and last accessed time of a file or folder are important factors that can indicate events that have affected a computer system. The form of the time information varies with the file system, depending on the user's actions such as copy, transfer, or network transport of files. Specific changes of the time information may be of considerable help in analyzing the user's actions in the computer system. This paper analyzes changes in the time information of files and folders for different operations of the NTFS and attempts to reconstruct the user's actions.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.73-90
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• 2015

When we apply file commands on files in a directory, the directory as well as the file suffer changes in timestamps of MFT entry. Based on understanding of these changes, this work provides a digital forensic analysis on the timestamp changes of the directory influenced by execution of file commands. NTFS utilizes B-tree indexing structure for managing efficient storage of a huge number of files and fast lookups, which changes an index tree of the directory index when files are operated by commands. From a digital forensic point of view, we try to understand behaviors of the B-tree indexes and are looking for traces of files to collect information. But it is not easy to analyze the directory index entry when the file commands are executed. And researches on a digital forensic about NTFS directory and B-tree indexing are comparatively rare. Focusing on the fact, we present, in this paper, directory timestamp changes after executing file commands including a creation, a copy, a deletion etc are analyzed and a method for finding forensic evidences of a deletion of directory containing files. With some cases, i.e. examples of file copy and file deletion command, analyses on the problem of timestamp changes of the directory are given and the problem of finding evidences of a deletion of directory containging files are shown.

• Restorative Dentistry and Endodontics
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• v.31 no.3
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• pp.161-168
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• 2006

During root canal preparation procedures, the potential for instrument separation is always present. Files, a lentulo, a Gates-Glidden (GG) bur or any manufactured obstruction can be left behind in the canal Nickel-titanium (NiTi) rotary files are in common usage in these days. Despite their undeniable advantages, there is a potential risk of separation within the canals. It is very rapid, unpredictable, and creates a great deal of stress for the practitioner. When an endodontic instrument separates, the best option is to remove it. Ultrasonic instruments and microscopes have improved the success rate for removing separated instruments. But It is difficult and not always possible. Therefore prevention is the key. In this case report, several management methods of separated file in the canal are presented.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.87-93
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• 2013

In this research, a new methodology to perform building energy analysis using Industry Foundation Classes (IFC) standard has been studied. With the help of Archicad 14 modeling software, a 3D test model is generated and then exported to IFCXML format. A ruby code program retrieves the building information from the resulting IFCXML file using Nokogiri library. An INP file is created and gets ready for next energy analysis step. DOE 2.2 program analyzes the INP file and gives a detailed report of the energy cost of the building. Case study shows when using the IFC standard method, the Interoperability of the energy analysis is greatly improved. The main stream 3D building modeling software supports IFC standard. DOE 2.2 is able to read the INP file generated by IFC file. This means almost any 3D model created by main stream modeling software can be analyze in terms of energy cost Thus, IFC based energy analysis method has a promising future. With the development and application of IFC standard, designers can do more complex and easy-to-run energy analysis in a more efficient way.

• Journal of Information Processing Systems
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• v.16 no.2
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• pp.301-317
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• 2020

An enterprise patch-management system (PMS) typically supplies a single point of failure (SPOF) of centralization structure. However, a Blockchain system offers features of decentralization, transaction integrity, user certification, and a smart chaincode. This study proposes a Hyperledger Fabric Blockchain-based distributed patch-management system and verifies its technological feasibility through prototyping, so that all participating users can be protected from various threats. In particular, by adopting a private chain for patch file set management, it is designed as a Blockchain system that can enhance security, log management, latest status supervision and monitoring functions. In addition, it uses a Hyperledger Fabric that owns a practical Byzantine fault tolerant consensus algorithm, and implements the functions of upload patch file set, download patch file set, and audit patch file history, which are major features of PMS, as a smart contract (chaincode), and verified this operation. The distributed ledger structure of Blockchain-based PMS can be a solution for distributor and client authentication and forgery problems, SPOF problem, and distribution record reliability problem. It not only presents an alternative to dealing with central management server loads and failures, but it also provides a higher level of security and availability.

• ETRI Journal
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• v.33 no.1
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• pp.128-131
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• 2011

This letter describes a file format designed for interactive music service where users are able to recompose music based on their own preferences. The proposed design utilizes the flexible features of the ISO base media file format (ISO/IEC 14496-12, ISO-BMFF). The techniques offered in the proposed file format enable compact storage and efficient preset management, allowing users to recompose music with ease and convenience. Additionally, an implementation scheme for an interactive music player is shown along with its results.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.3
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• pp.139-150
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• 2015

The major components of IoT(Internet of Things) environment are IoT devices rather than the conventional desktop computers. One of the intrinsic characteristics of IoT devices is diversity in view of data type and data access method. In addition, IoT devices usually deal with real-time data. In order to use such IoT data for internal business or cloud services, an IoT platform capable of easy domain management and consistent data access interface is required. This paper proposes a Linux FUSE-based virtual file system connecting IoT devices on POSIX file system view. It is possible to manage IoT domain with the native Linux utilities such as mkdir, mknod, ls and find in the file system. Also, the file system makes it possible to access or control IoT devices through POSIX interface such as open(), read(), write() or close() without any separate APIs or utilities. A test result shows that the management performance of the file system is lower than that of linux file system negligibly.

• The KIPS Transactions:PartC
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• v.13C no.3 s.106
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• pp.275-282
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• 2006

There are several independent applets to support various applications in a Java Card. Each applet in a Java Card processes and manages its own data without concern to other applets and their data. In this paper we proposed file system API to support efficient file management based on Java Card. Also we designed and implemented Java Card based file system API using basic API and referring to the file system standard defined in ISO 7816-4 Smart Card standard. By using proposed file system API, we can replace duplications of same code in each applet with short method call. So the used memory space and processing time is reduced and also the reduction of development time and cost will be expected.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.3
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• pp.155-178
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• 2019

The study aims to analyze the characteristics and problems of raw image file formats, evaluate its suitability for the management of digital photographic records, and suggest the introduction method to utilize such format in public institutions. Raw image file formats feature reversibility and flexibility. However, most of them are proprietary file formats that depend on the digital camera manufacturer. The DNG format, which was developed to standardize raw image file formats, has received positive reviews from overseas public agencies. However, the DNG format is not fully recognized as a standard; hence, it is appropriate to use it tentatively until the standard raw format appears. On the other hand, the converted digital photo file format is not recognized as an original with legal authenticity. Therefore, in the short term, DNG files created by format conversion and original raw files should be encapsulated and preserved. Furthermore, it is necessary to redefine the baseline of the hash value and file size to recognize the legal authenticity only with DNG files in the long term.

• Restorative Dentistry and Endodontics
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• v.48 no.4
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• pp.38.1-38.10
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• 2023

Objectives: The aim of this study was to examine the use of hand or rotary files by pre-graduation (fourth- and fifth-year) and postgraduate students in endodontic treatments and to determine the incidence of file fracture and the management of cases with broken instruments. Materials and Methods: A total of 2,168 teeth undergoing primary endodontic treatment were included in this study. It was determined that 79 of these teeth resulted in broken tools. In the case of broken tools, the education level of the treating clinician, the tooth that was being treated, the canal and fracture level, the curvature of the tooth and the management of the broken instrument were recorded. Periapical radiographs of the patients were used to calculate curvature following the Schneider method. Results: There was no significant difference in the incidence of broken tools according to education level (p > 0.05). The incidence of file fracture in molar teeth (73.4%) was higher than in other teeth (p < 0.05). More files were broken in the mandibular molar MB canal (20.25%) and in the apical third of the canals (72.1%). The risk of instrument fracture was high in teeth with moderate (44.3%) and severe (38%) curvature canals. The management of apically broken (80%) files mostly involved lefting (p < 0.05). Conclusions: There was no statistically significant difference between fourth-year students, fifth-year students and postgraduate students in terms of instrument fracture.