• Title/Summary/Keyword: X-Tree

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Hash Tree based Communication Protocol in V2X Environments Including Internet of Vehicles for Providing Secure Vehicular Communication Services (차량인터넷을 포함한 V2X 환경에서 안전한 차량 통신 서비스 제공을 위한 해시 트리 기반 통신 프로토콜)

  • Jin, Byungwook;Cha, Siho
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.14 no.1
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    • pp.27-34
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    • 2018
  • Various messages generated in vehicles are transmitted based on the wireless telecommunication which is a core technology of vehicle to everything (V2X). However, the hackers attack them upon penetration to the system and network to cause the generation of users' inconveniences for vehicular communication. Moreover, huge damage could be occurred in terms of physical and materialistic areas if the users in the vehicles were attacked in the communication environment. Therefore, this study was to design the safe communication protocol using hash tree technique in the V2X environments. Using hash tree technique, processes of issuing certificate and registration and communication protocol were designed, and safety analysis was performed on the attacking technique which is occurred in the existing vehicles. Approximately 62% of decrease in the capacity analysis was found upon comparative analysis of telecommunication processes with the system to issue the certificate which is used in the existing vehicles.

FastIO: High Speed Launching of Smart TV Apps (FastIO: 스마트 TV 앱의 고속 구동 기법)

  • Lee, Cheolhee;Hwang, Taeho;Won, Youjip;Lee, Seongjin
    • Journal of KIISE
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    • v.43 no.7
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    • pp.725-735
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    • 2016
  • Smart TV uses Webkit as a web browser engine to provide contents such as web surfing, VOD watching, and games. Webkit uses web resources, such as HTML, CSS, JavaScript, and images, in order to run applications. At the start of an application, Webkit loads resources to the memory and creates DOM tree and render tree, which is a time consuming process. However, DOM tree and render tree created by the smart TV application do not change over time because the smart TV application uses web resources stored in a disk. If DOM tree and render tree can be stored and reused, it is possible to reduce loading time of an application. In this paper, we propose FastIO technique that selectively adds persistency to dynamically allocated memory. FastIO reduces overall application loading time by eliminating the process of loading resources from storage, parsing the HTML documents, and creating DOM tree and render tree. Comparison of the application resource loading times indicates that the web browser with FastIO is 7.9x, 44.8x, and 2.9x faster than the legacy web browser in an SSD, Ramdisk, and eMMC environment, respectively.

CS-Tree : Cell-based Signature Index Structure for Similarity Search in High-Dimensional Data (CS-트리 : 고차원 데이터의 유사성 검색을 위한 셀-기반 시그니쳐 색인 구조)

  • Song, Gwang-Taek;Jang, Jae-U
    • The KIPS Transactions:PartD
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    • v.8D no.4
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    • pp.305-312
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    • 2001
  • Recently, high-dimensional index structures have been required for similarity search in such database applications s multimedia database and data warehousing. In this paper, we propose a new cell-based signature tree, called CS-tree, which supports efficient storage and retrieval on high-dimensional feature vectors. The proposed CS-tree partitions a high-dimensional feature space into a group of cells and represents a feature vector as its corresponding cell signature. By using cell signatures rather than real feature vectors, it is possible to reduce the height of our CS-tree, leading to efficient retrieval performance. In addition, we present a similarity search algorithm for efficiently pruning the search space based on cells. Finally, we compare the performance of our CS-tree with that of the X-tree being considered as an efficient high-dimensional index structure, in terms of insertion time, retrieval time for a k-nearest neighbor query, and storage overhead. It is shown from experimental results that our CS-tree is better on retrieval performance than the X-tree.

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Exploring Relationships between Urban Tree Plantings and Microclimate Amelioration (도시 수목식재와 미기후 개선의 상관성 구명)

  • Jo, Hyun-Kil;Ahn, Tae-Won
    • Journal of the Korean Institute of Landscape Architecture
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    • v.34 no.5 s.118
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    • pp.70-75
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    • 2006
  • The purpose of this study is to explore the effects of difference in urban tree plantings on microclimate amelioration, and to suggest essential information for quantifying urban energy budgets and energy savings. This study was focused on measuring and analyzing air temperature and relative humidity in summer. Daytime air temperatures at places with 8%, 24%, 44%, 79%, and 100% cover of woody plants were, respectively, $0.6^{\circ}C,\;1.3^{\circ}C,\;2.4^{\circ}C,\;3.5^{\circ}C,\;and\;4.8^{\circ}C$ cooler, compared to a place with 0% cover. A 10% increase of woody plant cover was estimated to reduce the temperature by approximately $0.55^{\circ}C$. The temperature reduction effects were relatively greater between places with lower cover of woody plants than between those with higher cover. Woody plant cover and crown volume were the appropriate indicators which quantified the effects of tree plantings on air temperatures, based on the correlation analysis. Regression equations to estimate temperature change ($Y:^{\circ}C$) using woody plant cover ($X_1:%$) or crown volume ($X_2:m^3$) as independent variables are as follows: $$1nY=3.3233-0.0018X_1\;(r^2=0.99,\;p<0.0001)\;Y=27.5297-0.0019X_2\;(r^2=0.96,\;p=0.0007)$$

Program Plagiarism Detection based on X-treeDiff+ (X-treeDiff+ 기반의 프로그램 복제 탐지)

  • Lee, Suk-Kyoon
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.47 no.4
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    • pp.44-53
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    • 2010
  • Program plagiarism is a significant factor to reduce the quality of education in computer programming. In this paper, we propose the technique of identifying similar or identical programs in order to prevent students from reckless copying their programming assignments. Existing approaches for identifying similar programs are mainly based on fingerprints or pattern matching for text documents. Different from those existing approaches, we propose an approach based on the program structur. Using paring progrmas, we first transform programs into XML documents by representing syntactic components in the programs with elements in XML document, then run X-tree Diff+, which is the change detection algorithm for XML documents, and produce an edit script as a change. The decision of similar or identical programs is made on the analysis of edit scripts in terms of program plagiarism. Analysis of edit scripts allows users to understand the process of conversion between two programs so that users can make qualitative judgement considering the characteristics of program assignment and the degree of plagiarism.