• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.135-140
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• 2017

This paper is on a study for discrimination on relative sequence as a most actively discussed topic in forensic document fields. This paper describes the application of the visual spectral comparator and infinite focus microscope as observation methods for overlapping region of printing and writing lines. As a result, we could categorize overlapping region images and identify the sequence of printing and writing lines by various inks.

• Analytical Science and Technology
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• v.17 no.4
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• pp.315-321
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• 2004

The aim of this study was to investigate the evidential value of blue and black ballpoint pens on paper by nondestructive techniques. In this work, 21 blue and 22 black ballpoint pens which were purchased on different brands were analyzed by Raman Spectroscopy and Video Spectral Comparator (VSC). Surface-Enhanced Resonance Raman Spectroscopy (SERRS) with excitation at 685 nm and VSC with several spot light filters were used for the discrimination of ballpoint pen inks. In the SERR spectra, the ballpoint pen inks on paper could be shown sharp spectral bands and distinguished by their band shapes and relative intensities. In the blue and black ballpoint pen inks, the discriminating powers (DP) by SERRS were 0.85 and 0.67 and the DP by VSC were 0.88 and 0.90, respectively. The DP by combined sequence of techniques was all 0.97 in both black and blue ballpoint pen inks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.05a
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• pp.463-466
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• 2012

Smartphones along with the development of crime evidence has been using smartphones. Phone's internal storage medium can be used as evidence in the case of images, video, phone, GPS information, there are Internet access and other data records. Therefore, these data to collect evidence of a systematic procedure for collecting and analyzing evidence is needed. In this paper, the target mobile phone forensics forensic evidence collection, evidence analysis, and reporting results to the procedures and how to draw. Through this paper, phone forensics and will serve as a basis for the investigation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2427-2432
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• 2014

Color-$X^2$ is used as a method for scene change detection. It extracts a violent scene in an elevator and then could be used for real-time surveillance of criminal acts. The scene could be also used to secure after-discovered evidences and to prove analysis processes. Video Forensic is defined as a research on various methods to efficiently analyze evidences upon crime-related visual images in the field of digital forensic. The method to use differences of color-histogram detects the difference values of histogram for RGB color from two frames respectively. Our paper uses Color-$X^2$ histogram that is composed of merits of color histogram and ones of $X^2$ histogram, in order to efficiently extract violent scenes in elevator. Also, we use a threshold so as to find out key frame, by use of existing Color-$X^2$ histogram. To increase the probability that discerns whether a real violent scene or not, we take advantage of statistical judgments with 20 sample visual images.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2153-2158
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• 2016

Multimedia such as image, audio, and video is easy to create and distribute with the advance of IT. Since novice uses them for illegal purposes, multimedia forensics are required to protect contents and block illegal usage. This paper presents a multimedia forensic algorithm for video to identify the device used for acquiring unknown video files. First, the way to calculate a sensor pattern noise using Wiener filter (W-SPN) is presented, which comes from the imperfection of photon detectors against light. Then, the way to identify the device is explained after estimating W-SPNs from the reference device and the unknown video. For the experiment, 30 devices including DSLR, compact camera, smartphone, and camcorder are tested and analyzed quantitatively. Based on the results, the presented algorithm can achieve the 96.0% identification accuracy.

• Journal of KIISE
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• v.45 no.3
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• pp.311-320
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• 2018

Recently, the use of digital audio and video as proof in criminal and all kinds of litigation is increasing, and scientific investigation using digital forensic technique is developing. With the development of computing and file editing technologies, anyone can simply manipulate video files, and the number of cases of manipulating digital data is increasing. As a result, the integrity of the evidence and the reliability of the evidence Is required. In this paper, we propose a technique for extracting the Electrical Network Frequency (ENF) through a grid of power grids according to the geographical environment for power supply, and then performing signal processing for peak detection using QIFFT. Through the detection algorithm using the standard deviation, it was confirmed that the video file was falsified with 73% accuracy and the forgery point was found.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.1
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• pp.27-34
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• 2021

In this paper, we propose a copyright protection scheme for real-time streaming of HEVC(High Efficiency Video Coding) based realistic content. Previous research uses encryption and modular operation for copyright pre-protection and copyright post-protection, which causes delays in ultra high resolution video. The proposed scheme maximizes parallelism by using thread pool based DRM(Digital Rights Management) packaging with only HEVC's CABAC(Context Adaptive Binary Arithmetic Coding) codec and GPU based high-speed bit operation(XOR), thus enabling real-time copyright protection. As a result of comparing this scheme with previous research at three resolutions, PSNR showed an average of 8 times higher performance, and the process speed showed an average of 18 times difference. In addition, as a result of comparing the robustness of the forensic mark, the filter and noise attack, which showed the largest and smallest difference, with a 27-fold difference in recompression attacks, showed an 8-fold difference.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.2
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• pp.323-331
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• 2013

There are three ways how to extract forensic evidence from mobile phone, such as SYN, JTAG, Revolving. However, it should be a different way to extract forensic evidence due to the differences of their usage and technology between them(mobile phone and smart phone). Therefore, in this paper, I will come up with extraction method that forensics evidence by search and seizure of a smart phone. This study aims to analyze specifications and O.S., backup analysis, evidence in smart to analyze for search and seizure of a smart phone commonly used google android and windows mobile smart phone. This study also aim to extract forensics evidence related to google android and phone book, SMS, photos, video of window mobile smart phone to make legal evidence and forensics report. It is expected that this study on smart phone forensics technology will contribute to developing mobile forensics technology.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.11
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• pp.427-438
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• 2016

Car blackboxes record the information and status of driving. Since blackboxes are commonly used in daily life, the usage of video data recorded from blackboxes is increasing for investigating. Investigators use a own analysis tool suitable for their blackbox provided by the manufacturer in order to check the data. But the tools are not enough to use in the digital forensic analysis because they are dependent on a specific model of blackbox and provides ungeneralized functions. Moreover, if the manufacturer is bankrupt, then their own tools can not be obtained also. Therefore, the way data are stored in the blackboxes which are now in the market are investigated and the features and limitations which have blackbox's own analysis tools are checked. And a comprehensive tool for the analysis of blackboxes is designed and implemented as in this paper.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.11
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• pp.465-472
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• 2022

In this paper, the style synthesis network is trained to generate style-synthesized video through the style synthesis through training Stylegan and the video synthesis network for video synthesis. In order to improve the point that the gaze or expression does not transfer stably, 3D face restoration technology is applied to control important features such as the pose, gaze, and expression of the head using 3D face information. In addition, by training the discriminators for the dynamics, mouth shape, image, and gaze of the Head2head network, it is possible to create a stable style synthesis video that maintains more probabilities and consistency. Using the FaceForensic dataset and the MetFace dataset, it was confirmed that the performance was increased by converting one video into another video while maintaining the consistent movement of the target face, and generating natural data through video synthesis using 3D face information from the source video's face.