Hisao OGATA Tomoyoshi ISHIKAWA Norichika MIYAMOTO Tsutomu MATSUMOTO
Recently, criminals frequently utilize logical attacks to Automated Teller Machines (ATMs) and financial institutes' (FIs') networks to steal cash. We proposed a security measure utilizing peripheral devices in an ATM for smart card transactions to prevent “unauthorized cash withdrawals” of logical attacks, and the fundamental framework as a generalized model of the measure in other paper. As the measure can prevent those logical attacks with tamper-proof hardware, it is quite difficult for criminals to compromise the measure. However, criminals can still carry out different types of logical attacks to ATMs, such as “unauthorized deposit”, to steal cash. In this paper, we propose a security measure utilizing peripheral devices to prevent unauthorized deposits with a smart card. The measure needs to protect multiple transaction sub-processes in a deposit transaction from multiple types of logical attacks and to be harmonized with existing ATM system/operations. A suitable implementation of the fundamental framework is required for the measure and such implementation design is confusing due to many items to be considered. Thus, the measure also provides an implementation model analysis of the fundamental framework to derive suitable implementation for each defense point in a deposit transaction. Two types of measure implementation are derived as the result of the analysis.
Toru YAMADA Yoshihiro MIYAMOTO Masahiro SERIZAWA Takao NISHITANI
This paper proposes a video-quality estimation method based on a reduced-reference model for realtime quality monitoring in video streaming services. The proposed method chooses representative-luminance values for individual original-video frames at a server side and transmits those values, along with the pixel-position information of the representative-luminance values in each frame. On the basis of this information, peak signal-to-noise ratio (PSNR) values at client sides can be estimated. This enables realtime monitoring of video-quality degradation by transmission errors. Experimental results show that accurate PSNR estimation can be achieved with additional information at a low bit rate. For SDTV video sequences which are encoded at 1 to 5 Mbps, accurate PSNR estimation (correlation coefficient of 0.92 to 0.95) is achieved with small amount of additional information of 10 to 50 kbps. This enables accurate realtime quality monitoring in video streaming services without average video-quality degradation.
Kazuya NISHIHORI Yasuyuki MIYAMOTO
In this paper, we describe the effect of p-regions on the I-V kink in GaAs FETs. A kink-free p-pocket-type self-aligned gate GaAs MESFET (PP-MESFET), which does not include p-regions under the channel, has been analyzed and compared with a conventional buried-p-type self-aligned gate GaAs MESFET (BP-MESFET) using two-dimensional device simulation. The relation between the I-V kink and the layout of p-regions has been demonstrated by numerical simulation for the first time. For both the BP-MESFET and PP-MESFET, impact ionization produces holes in high-field regions. The holes accumulate under the channel, widen the channel, and cause an abrupt increase in drain current in turn in the BP-MESFET. On the other hand, in the PP-MESFET, holes generated in the high-field region are transported to the source region easily over the lower barrier owing to the absence of p-regions under the channel. Holes do not accumulate under the channel, leading to kink-free I-V characteristics of the PP-MESFET. P-regions should be located so as not to cause the accumulation of holes in GaAs FETs where p-regions are required for high-frequency performance.