Browsing by Author "Liu, Tsung-Yuan"

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A Distributed Multi-Dimensional Publications Management System
(2009-09-01)
Liu, Tsung-Yuan
;
Joung, Yuh-Jzer
;
資訊工程學系
;
Department of Computer Science
Conventional hierarchical organizations are inadequate in managing publications which are inherently multi-dimensional. The rigid hierarchical organization limits a user to a small number of navigable paths, and ambiguities arise on the preferred location of an object. Prior research on enhanced browsing or information visualization suffers from the curse of dimensionality and is limited by the interaction usability and/or the computational efforts required. This paper proposes a hypercube object space for modeling an interactive browsing methodology, called multi-dimensional browsing, along with an integrated, powerful, yet simple interface for navigating the object space. The entire navigation control is displayed as one concept hierarchy tree, allowing a user to navigate the object space by refining and generalizing multi-dimensional search criteria incrementally with strong feedback - but without the major drawbacks of prior research. A cross-platform, peer-to-peer architecture and modular implementation is also prototyped in Java to support the concept and to demonstrate its feasibility in handling thousands of publications.
Data Hiding in Graphic Drawings by Structures of Object Groupings
(2011-05-01)
Liu, Tsung-Yuan
;
Tsai, Wen-Hsiang
;
資訊工程學系
;
Department of Computer Science
A new data hiding method is proposed for embedding a bit-string message into the structure of object groupings in a drawing. The objects in a drawing are grouped skillfully according to the message data to be embedded as well as the inter-object distance relationships between the objects. The groupings of objects in the resulting stego-drawing are visually imperceptible and robust against translation, scaling, rotation, and mirroring attacks. Possibilities of embedding variable-length message data into drawings are demonstrated for different data hiding applications, including data authentication, copyright protection, and covert communication. The method can be applied to a variety of graphic drawings, including flowcharts, network diagrams, circuit schematics, floor plans, etc. Good results obtained from experiments conducted on Microsoft Visio drawings are shown to confirm the feasibility of the proposed method.
Generic Lossless Visible Watermarking-A New Approach
(2010-05-01)
Liu, Tsung-Yuan
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Tsai, Wen-Hsiang
;
資訊工程學系
;
Department of Computer Science
A novel method for generic visible watermarking with a capability of lossless image recovery is proposed. The method is based on the use of deterministic one-to-one compound mappings of image pixel values for overlaying a variety of visible watermarks of arbitrary sizes on cover images. The compound mappings are proved to be reversible, which allows for lossless recovery of original images from watermarked images. The mappings may be adjusted to yield pixel values close to those of desired visible watermarks. Different types of visible watermarks, including opaque monochrome and translucent full color ones, are embedded as applications of the proposed generic approach. A two-fold monotonically increasing compound mapping is created and proved to yield more distinctive visible watermarks in the watermarked image. Security protection measures by parameter and mapping randomizations have also been proposed to deter attackers from illicit image recoveries. Experimental results demonstrating the effectiveness of the proposed approach are also included.
New steganographic method for data hiding in Microsoft Word documents by a change tracking technique
(2007-03-01)
Liu, Tsung-Yuan
;
Tsai, Wen-Hsiang
;
資訊工程學系
;
Department of Computer Science
A new steganographic method for data hiding in Microsoft Word documents by a change tracking technique is proposed. The data embedding is disguised such that the stegodocument appears to be the product of a collaborative writing effort. Text segments in the document are degenerated, mimicking to be the work of an author with inferior writing skills, with the secret message embedded in the choices of degenerations. The degenerations are then revised with the changes being tracked, making it appear as if a cautious author is correcting the mistakes. The change tracking information contained in the stegodocument allows the original cover, the degenerated document, and, hence, the secret message to be recovered. The extra change tracking information added during message embedding is vital in a normal collaboration scenario, and so hinders ignorant removals by skeptics. Experiments demonstrate the feasibility of the proposed method.
Quotation Authentication: A New Approach and Efficient Solutions by Cascaded Hashing Techniques
(2010-12-01)
Liu, Tsung-Yuan
;
Tsai, Wen-Hsiang
;
資訊工程學系
;
Department of Computer Science
A new approach to efficient authentication of quotations from trusted sources but embedded in messages created by unknown authors is proposed. Two different techniques for efficient generation of authenticable quotations using cascaded hashing are proposed for conventional quotations, and an efficient two-dimensional signature generation technique is proposed for two-dimensional quotations from spreadsheets. A technique for associating the signature with the quotation in the Microsoft Word document is also proposed for generation of integrated authenticable quotations that survive copy-and-paste operations.