Conventional localization techniques such as triangulation and multilateration are not reliable in non-line-of-sight (NLOS) environments such as dense urban areas. Although fingerprint-based localization techniques have been proposed to solve this problem, we may face difficulties because we do not know the parameters of the illegal radio when creating the fingerprint database. This paper proposes a novel technique to localize illegal radios in an urban environment by interpolating the channel impulse responses stored as fingerprints in a database. The proposed interpolation technique consists of interpolation in the bandwidth (delay), frequency and spatial domains. A localization algorithm that minimizes the squared error criterion is employed in this paper, and the proposed technique is evaluated through Monte Carlo simulations using location fingerprints obtained from ray-tracing simulations. Results show that utilizing an interpolated fingerprint database is advantageous in such scenarios.

For mission-critical and safety-critical systems such as medical, financial, or administrative information systems, a secure and reliable storage system is indispensable. The main purpose of our research is to develop a highly secure and highly reliable storage system. We have proposed a storage system that utilizes a secret sharing scheme. The storage system is called the Secret Sharing Storage System. So far, we have developed a prototype of the storage system. In this paper, we propose an automatic repair mechanism, and an interval decision method for this system.