Hiroshi Yoshiura

General quality maintenance module for motion picture watermarking

This paper proposes a novel control module that can be incorporated in a wide range of digital watermarking systems and that controls system watermarking processes to preserve picture quality.

An evaluation point culling algorithm for radio propagation simulation based on the imaging method

This paper presents a three-dimensional radio propagation simulation technique that reduces its computation time. The technique is based on the imaging method, which is one of the ray tracing methods. First, the probability that propagation paths exist at evaluation points within second-order reflection is shown. The result shows that the probability is less than a few percents. Therefore, it appears that the computation time can be reduced by eliminating the calculation for evaluation points where rays never launch. Second, the algorithm implemented the idea is presented. The algorithm uses “approximated illumination area. ” There aren ′t any evaluation points outside the area. The area is solved from the coordinate relationships between the last reflected object and the last imaging point. The last imaging point is derived from recursive image generation of the transmitting point. After that, only evaluation points within the illuminated area are calculated. The computation time can be reduced to less than one-quarter of the time previously required because the calculation for evaluation points where rays don′t launch never be executed. The accuracy of the proposed method is not degraded since the method just eliminates redundancy of the path determination part of the conventional imaging method.

INTERNET-MARKs: Clear, Secure, and Portable Visual Marks for the Cyber Worlds

Visual marks play critical roles in the physical world, but their use in the cyber world is limited because there they are easy to forge, tamper with and copy onto unauthorized data. This paper therefore describes a new type of visual marks that are secure because digital signatures are embedded in them and that can be used with a wide variety of cyber-world systems. It also shows the effectiveness of these marks by describing their application to WWW site authentication.

Authenticating Web-Based Virtual Shops Using Signature-Embedded Marks - A Practical Analysis

Authenticating Web-based virtual shops is a critical problem in establishing electronic commerce as a social infrastructure. One solution is to use guarantee marks pasted on the Web pages of the virtual shops. However, its effectiveness depends on the reliability of the marks. This paper proposes a verifiable mark system in which digital signatures are embedded in the marks. A prototype authentication system based on this mark system was implemented and evaluated from practical viewpoints. The results show its feasibility.

Combinatorial Optimization of Countermeasures against Illegal Copying

The growth of the Internet has lead to an increase in the distribution on digital contents, such as music, still pictures, and motion pictures through networks. However, it has also lead to an increase in illegal copying without permission from the copyright holder. Although a number of countermeasures against illegal copying have been developed including watermarking and contents capsulation, it is impossible to find one perfect countermeasure. A method is needed that would allow for an optimal combination of different countermeasures to substantially reduce the probability of illegal copying. We propose such a method based on combinatorial optimization and fault-tree analysis. We use this method for a number of cases and show the actual optimal combinations for each case, as well as a flow chart for selecting a proper combination of countermeasures depending on the situation.

Improved video watermarking for MPEG encoders using motion analysis

This paper proposes a new watermarking method, which uses motion analysis to allocate watermarks where they will be less perceptible and thus improves their transparency. The proposed method would be most effective when incorporated into MPEG encoders and could be widely used in consumer electronics.

A Multi-OS Approach to Trusted Computer Systems

Trusted computer systems are becoming increasingly important in private sectors such as banking and insurance, but those currently available are inconvenient in private sectors because they were developed for use by government agencies and the military. This paper describes how a trusted system can be made from an ordinary OS for daily use and a secure OS monitoring that OS. This configuration is implemented by using the multi-OS control technique. Analysis of an example system confirms the feasibility of the proposed method and even implies that a trusted system can be implemented by having two ordinary OSs that monitor each other.