• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.41-44
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• 2008

In this paper, major species of tree were discriminated in compartment by using LiDAR data and optic imagery. This is an important work in forest field. A current digital stock map has created the aerial photo and collecting survey data. Unlike high resolution imagery, LiDAR data is not influenced by topographic effects since it is an active sensory system. LiDAR system can measure three dimension information of individual tree. And the main methods of this study were to extract reliable the individual tree and analysis techniques to facilitate the used LiDAR data for calculating tree crown 2D parameter. We should estimate the forest inventory for calculating parameter. 2D parameter has need of area, perimeter, diameter, height, crown shape, etc. Eventually, major species of tree were determined the tree parameters, compared a digital stock map.

• 디지털산업정보학회논문지
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• 제11권2호
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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.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권7호
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• pp.3284-3306
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• 2018

This study proposes a method to develop an authoring system(GeoMaTree) for diverse trees that constitute a virtual landscape. The GeoMaTree system enables the simple, intuitive production of an efficient structure, and supports real-time processing. The core of the proposed system is a procedural modeling based on a mathematical model and an application that supports digital content creation on diverse platforms. The procedural modeling allows users to control the complex pattern of branch propagation through an intuitive process. The application is a multi-resolution 3D model that supports appropriate optimization for a tree structure. The application and a compatible function, with commercial tools for supporting the creation of realistic synthetic images and virtual landscapes, are implemented, and the proposed system is applied to a variety of 3D image content.

• International Journal of Internet, Broadcasting and Communication
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• 제14권3호
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• pp.8-16
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• 2022

In this paper, we propose a method of reconstructing the file system to obtain digital forensics information from the APFS file system when meta information that can know the structure of the file system is deleted due to partial damage to the disk. This method is to reconstruct the tree structure of the file system by only retrieving the B-tree node where file/directory information is stored. This method is not a method of constructing nodes based on structural information such as Container Superblock (NXSB) and Volume Checkpoint Superblock (APSB), and B-tree root and leaf node information. The entire disk cluster is traversed to find scattered B-tree leaf nodes and to gather all the information in the file system to build information. It is a method of reconstructing a tree structure of a file/directory based on refined essential data by removing duplicate data. We demonstrate that the proposed method is valid through the results of applying the proposed method by generating numbers of user files and directories.

• 디지털산업정보학회논문지
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• 제9권3호
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• pp.79-89
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• 2013

This paper proposes a watermarking scheme to protect ownership of a digital hologram, an ultra-high value-added content. It performs pre-defined levels of quad-tree Fresnelet transforms. The relationship among the same-positional-blocks is extracted as the digital pre-watermark. For the relationship, we use properties of a digital hologram that a hologram pixel retains all the information of the object and that the same size of partial holograms reconstructs the same size of object but different in their view points. Also we mix a set of private data with the pre-watermark and the result is encrypted by a block cipher algorithm with a private key. Experimental results showed that the proposed scheme is very robust for the various malicious and non-malicious attacks. Also because it extracts the watermarking data instead of inserting, the watermarking process does not harm the original hologram data. So, it is expected to be used effectively for invisible and robust watermark for digital holograms.

• ETRI Journal
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• 제36권3호
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• pp.450-459
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• 2014

In this paper, we present a new, easy-to-generate system that is capable of creating virtual 3D tree models and simulating a variety of growth processes of a tree from a single, real tree image. We not only construct various tree models with the same trunk through our proposed digital image matting method and skeleton-based abstraction of branches, but we also animate the visual growth of the constructed 3D tree model through usage of the branch age information combined with a scaling factor. To control the simulation of a tree growth process, we consider tree-growing attributes, such as branching orders, branch width, tree size, and branch self-bending effect, at the same time. Other invisible branches and leaves are automatically attached to the tree by employing parametric branch libraries under the conventional procedural assumption of structure having a local self-similarity. Simulations with a real image confirm that our system makes it possible to achieve realistic tree models and growth processes with ease.

• 한국게임학회 논문지
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• 제11권6호
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• pp.61-70
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• 2011

본 논문에서는 결정트리 학습 알고리즘을 활용한 축구 게임 수비 NPC 제어 방법을 제안한다. 제안하는 방법은 실제 게임 사용자들의 이동 방향 패턴과 행동 패턴을 추출하여 결정트리학습 알고리즘에 적용한다. 그리고 학습된 결정트리를 바탕으로 NPC의 이동방향과 행동을 결정한다. 실험결과 제안하는 방법은 결정트리 학습에 시간이 다소 걸리지만, 학습된 결정트리를 바탕으로 이동방향이나 행동을 결정하는 시간은 약 0.001-0.003 ms(밀리초)가 소요되어 실시간으로 NPC를 제어할 수 있었다. 또한, 제안하는 방법은 현재 상태 정보 뿐만 아니라 이를 분석한 관계정보, 이전 상태 정보도 함께 활용하므로, 기존방법인 (Letia98)에 비해 이동방향 결정시 높은 정확도를 나타냈다.

• 디지털산업정보학회논문지
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• 제6권3호
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• pp.49-57
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• 2010

We extended a general attack tree to apply cyber attack model for network vulnerability analysis. We defined an extended cyber attack tree (E-CAT) which extends the general attack tree by associating each node of the tree with a transition of attack that could have contributed to the cyber attack. The E-CAT resolved the limitation that a general attack tree can not express complex and sophisticate attacks. Firstly, the Boolean expression can simply express attack scenario with symbols and codes. Secondary, An Attack Generation Probability is used to select attack method in an attack tree. A CONDITION-composition can express new and modified attack transition which a aeneral attack tree can not express. The E-CAT is possible to have attack's flexibility and improve attack success rate when it is applied to cyber attack model.

• 한국컴퓨터정보학회논문지
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• 제22권8호
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• pp.73-83
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• 2017

In this paper, we discuss the differences between an ordinary B-tree and B-tree implemented by NTFS. There are lots of distinctions between the two B-tree, if not understand the distinctions fully, it is difficult to utilize and analyze artifacts of NTFS. Not much, actually, is known about the implementation of NTFS, especially B-tree index for directory management. Several items of B-tree features are performed that includes a node size, minimum number of children, root node without children, type of key, key sorting, type of pointer to child node, expansion and reduction of node, return of node. Furthermore, it is emphasized the fact that NTFS use B-tree structure not B+structure clearly.

• 디지털산업정보학회논문지
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• 제7권3호
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• pp.43-53
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• 2011

The many cities are changing in the city form where the person and nature are mixed. Namely, the government invests many expense in tree field of distance space for the change in the green city. In this paper, we design and implement a tree growth management system using PDA built in 13.56MHz RFID reader and CBD(Component Based Development) for ubiquitous computing environments. Our system provides history management to increase business efficiency for location coordinate of tree and history information of tree which using RFID, the RFlD tag is attaching the new tree and that is inputting GPS location information in PDA and provides tree information of tree by location coordinate to history management. Finally, we show from a performance analysis that our system achieves about 85% average tree read rate of RFID under test scenario environments.