NAIST Graduate School of Information Science
| Date: | Friday, August 25th 2006 |
|---|---|
| Time: | 13:30 - 15:40 |
| Place: | L1 Lecture Room |
| Language: | English ( Oral Presentation ), English/Japanese ( Discussion ) |
| Co-Chairs: | Nozomi Kobayashi ( Computational Linguistics Lab. : COE promoted researcher ), Takahiro Hirofuchi ( Internet Architecture and Systems Lab. : COE promoted researcher ). |
Various software obfuscation techniques have been proposed. However, there are few discussions on proper use of these obfuscations against imaginable threats. An ad-hoc use of obfuscations cannot guarantee that a program is sufficiently protected by existing obfuscations. For a systematic use of obfuscations and the verification of the result, this presentation proposes a goal-oriented approach. As a case study, we define a security goal and a threat model and then, based on the model, we describe a guideline to protect the target program.
I'm researching an interface which is an example of the fusion of social networking and ubiquitous computing technologies. I introduce SCACS, a Social Context-Aware Communication System that facilitates face-to-face communications between old-timers and newcomers in a research community, by visualizing social networks though using a wearable interface. SCACS provides users with information on coauthor relationships in order to help users understand conversational partners' research background and relationships among them. In the presentation, I would like to illustrate the algorithm of the visualization in detail.
In this presentation, I present a reactance-domain modulation scheme for burst error reduction of ISDB-T (Integrated Services Digital Broadcasting for terrestrial) in slow fading environment. The Japanese DTTB (Digital Terrestrial Television Broadcasting) standard, ISDB-T, employ OFDM (Orthogonal Frequency Division Multiplexing) for its transmission scheme. Thanks to the efficient FEC (Forward Error Correction) with long-depth time interleaving, ISDB-T is capable of receiving the signal in severe fading channel. In slow fading environment, burst error deteriorates its performance because the fade duration exceeds the interleaving depth. To solve this problem, I propose a reactance domain modulation scheme, which virtually generates the fast fading for efficient use of time interleaving. Therefore, the proposed scheme can solve burst error problem in slow fading environment.
The next generation of wireless communications does not require only the increasing of bit rate to hundred mega bit per seconds (Mbps) up to giga bps (Gbps) but also frequency resource management. In this presentation, for the first time the novel design of a multiple access technique with user overloading is proposed. User overloading is a kind of frequency resource management to increase the efficiency of frequency reuse in wireless communications for more additional users. Our proposed design can be considered as a new model of multicarrier code dicvision multiple access (MC-CDMA) but capable of increasing the user capacity up to 2N+1 (overload = N+1) compared to the conventional MC-CDMA system. It means that 2N+1 users can be assigned by using only N subcarriers, while the conventional design is N subcarrier for N users. The results shown that the proposed design is robust in frequency selective fading environment and outperform the existing design by about 3-4dB improvement (1000-10,000 times better) at bit-error-rate (BER) of 10-5.
I introduce "Live E! project". This project is aiming to establish the platform to share all digital information, generated by sensor devices all over the world. Now, these devices are installed and operated individually by each organization. By sharing these digital information, we will be able to create new application, which can contribute to solve the environmental problems, to educate student, and to create new business.
In this presentation, a novel non-contact 3D display based on motion parallax is proposed. The 3D viewpoint of the user is measured by real-time non-contact measurement system. By moving the user's head position and watching a CG image which corresponds to the measured viewpoint, the user can perceive 3D information using a normal flat monitor. Basic experiments for depth perception using only one eye or both eyes of the user are conducted to show the feasibility of the system. The experimental results show that the perceived distance tend to be shorter than the real distance and that the user can perceive objects at fixed positions without binocular parallax when the floor and the walls are drawn together.