An economic cost model for network deployment and spectrum in wireless networks

We describe the basic economic theory of cost model for network deployment and spectrum in wireless networks. In particular, we develop a production function for wireless networks. With this production function model, we explore the technical rate of substitution and the elasticity of substitution in the production function for wireless network and find its insight for wireless network. Finally, we compare the engineering value of spectrum and economic value of spectrum

State Complexity of Regular Tree Languages for Tree Matching

We study the state complexity of regular tree languages for tree matching problem. Given a tree t and a set of pattern trees L, we can decide whether or not there exists a subtree occurrence of trees in L from the tree t by considering the new language L′ which accepts all trees containing trees in L as subtrees. We consider the case when we are given a set of pattern trees as a regular tree language and investigate the state complexity. Based on the sequential and parallel tree concatenation, we define three types of tree languages for deciding the existence of different types of subtree occurrences. We also study the deterministic top-down state complexity of path-closed languages for the same problem.</jats:p

Physical Origin and Generic Control of Magnonic Band Gaps of Dipole-Exchange Spin Waves in Width-Modulated-Nanostrip Waveguides

We report, for the first time, on a novel planar structure of magnonic-crystal waveguides, made of a single magnetic material, in which the allowed and forbidden bands of propagating dipole-exchange spin-waves can be manipulated by the periodic modulation of different widths in thin-film nanostrips. The origin of the presence of several magnonic wide band gaps and the crucial parameters for controlling those band gaps of the order of ~10 GHz are found by micromagnetic numerical and analytical calculations. This work can offer a route to the potential application to broad-band spin-wave filters in the GHz frequency range.Comment: 24 pages, 8 figure

Design and Implementation of Security OS: A Case Study

The importance of a security operating system (OS) with security-enhancing mechanisms at the kernel level, such as a reference monitor and a cryptographic file system, has been increasingly emphasized as the weaknesses and limitation of mechanisms at the user level have been revealed. However, when a system has only a reference monitor, the system is vulnerable to a low-level detour or a physical attack. In addition, when a system has only a cryptographic file system, the file system has a difficulty in protecting itself. To address these problems, we designed and developed a security OS with a reference monitor, a cryptographic file system, authentication limitation, and session limitation. Here we describe the model, its implementation, and its overheads