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Toshio HASEGAWA Tsuyoshi NISHIOKA Hirokazu ISHIZUKA Jun'ichi ABE Katsuhiro SHIMIZU Mitsuru MATSUI Shigeki TAKEUCHI
Quantum cryptography has two advantages in comparison with conventional cryptography: one is that its security is guaranteed by a fundamental physical law, and the other is that it can detect eavesdropping. In this paper, we focus on an experimental realization of quantum cryptography as a total security system. To realize this, we adopt an interferometric optical system using Faraday mirror and improve its optical system. We also utilize semiconductor laser at a short wavelength (830 nm). As a result, we have successfully implemented quantum cryptosystem including error correction and privacy amplification. We confirmed that key distribution was performed at a rate of 1.1 kbps with a 1.7% QBER (quantum bit error rate) over a distance of 200 m (optical fiber). We also show our experimental results over a distance of 1 km (optical fiber) at a rate of 0.76 kbps.
Takashi TOMITA Daisuke ISHII Toru MURAKAMI Shigeki TAKEUCHI Toshiaki AOKI
MATLAB/Simulink is the de facto standard tool for the model-based development (MBD) of control software for automotive systems. A Simulink model developed in MBD for real automotive systems involves complex computation as well as tens of thousands of blocks. In this paper, we focus on decision coverage (DC), condition coverage (CC) and modified condition/decision coverage (MC/DC) criteria, and propose a Monte-Carlo test suite generation method for large and complex Simulink models. In the method, a candidate test case is generated by assigning random values to the parameters of signal templates with specific waveforms. We try to find contributable candidates in a plausible and understandable search space, specified by a set of templates. We implemented the method as a tool, and our experimental evaluation showed that the tool was able to generate test suites for industrial implementation models with higher coverages and shorter execution times than Simulink Design Verifier. Additionally, the tool includes a fast coverage measurement engine, which demonstrated better performance than Simulink Coverage in our experiments.