Narrow Results

In this paper, we attempt to shed light on whether Japanese households are rational or if their behavior is influenced by culture and social norms by examining their saving and bequest behavior. To summarize our main findings, we find that Japan’s household saving rate showed great volatility, was often low and even negative and was high only during the 25-year period from around 1960 until the mid-1980s (if we exclude the war years) and that we can explain the high level of, and trends over time in, Japan’s household saving rate via various socioeconomic and policy variables. This seems to suggest that the Japanese are not a saving-loving people and that their saving behavior is not governed by culture and social norms. Moreover, the bequest behavior of the Japanese suggests that they are less altruistic toward their children and less reliant on their children than other peoples, suggesting that the alleged social norm of strong family ties in Japan is largely a myth, and that the Japanese do not appear to be appreciably more concerned about the continuation of the family line or the family business than other peoples, suggesting that the influence of the “ie” (family) system is apparently not so pervasive either. However, we argue that these findings do not necessarily mean that culture and social norms do not matter.

The central subject of this paper is the relation between the macro-level of the Society and the micro-level of its individuals. In complex real-life systems, this relationship is not trivial and even the result at the macro-level can be counter-intuitive. One of the first models that highlights this is the Sakoda and Schelling’s model of spatial segregation where a person uses a selfish rule to decide whether or not to leave his current place; on the basis of the ratio of “compatible” agents in the neighborhood of each individual, simulations have shown that tolerant agents group together beyond what their own tolerance imposes. This paper compares the macro-behavior arising from either selfish or altruist micro-motives; for this purpose, we propose agent-based computational models based, respectively, on selfishness, altruism and a mixture of both. Computational simulations show that (i) in a totally altruistic population, a vast majority becomes satisfied as if the agents were themselves selfish and end up spatially segregated; (ii) altruist micro-motives allow to reduce both the micro-macro gap and the segregation phenomenon; (iii) in a mixed population, the macro-effect depends both on the respective weight of each micro-motives and the allocation strategy.

Wireless Mesh Network (WMN) is a wired extension of multi-hop ad hoc network (MANET) which defines a new paradigm for broadband wireless Internet. A packet originating from a meshclient is relayed collaboratively in a multi-hop fashion by the intermediate mesh routers (MRs) towards the Internet Gateway (IGW). This is strictly true in a network managed by a single trusted authority. But, a WMN can be formed by a group of independent MRs operated by different service providers. It is a real challenge to establish a priori trust in a multi-operator WMN.

Unfortunately, the current thrust of research in WMNs, is primarily focused on developing multi-path routing protocols; and security is very much in its infancy. This book chapter provides a comprehensive coverage of various security issues pertinent to WMNs. We will systematically explore the vulnerabilities that can be exploited by attackers to conduct various attacks. We then provide a detailed description of some important security designs/proposals from industry and academia that will capture the current start-of-the-art solutions. We also cover key results from our research and other active researchers that have a great impact on the design of a secure WMN. Finally, we describe various open challenges which can catalyze new research efforts in this direction.