SDNsec: Forwarding Accountability for the SDN Data Plane

SDN promises to make networks more flexible, programmable, and easier to manage. Inherent security problems in SDN today, however, pose a threat to the promised benefits. First, the network operator lacks tools to proactively ensure that policies will be followed or to reactively inspect the behavior of the network. Second, the distributed nature of state updates at the data plane leads to inconsistent network behavior during reconfigurations. Third, the large flow space makes the data plane susceptible to state exhaustion attacks. This paper presents SDNsec, an SDN security extension that provides forwarding accountability for the SDN data plane. Forwarding rules are encoded in the packet, ensuring consistent network behavior during reconfigurations and limiting state exhaustion attacks due to table lookups. Symmetric-key cryptography is used to protect the integrity of the forwarding rules and enforce them at each switch. A complementary path validation mechanism allows the controller to reactively examine the actual path taken by the packets. Furthermore, we present mechanisms for secure link-failure recovery and multicast/broadcast forwarding.Comment: 14 page

Deteriorating Employment and Marriage Decline in Japan

As is the case in Western countries, more Japanese are marrying later or remaining unmarried and are postponing childbearing or staying childless. Previous studies revealed that those individuals who were unable to secure regular employment due to the serious recession between the mid-1990s and mid-2000s, labelled a "lost generation," had a very low marriage rate. But what about subsequent cohorts? Using a discrete-time logit model to analyse Japanese Life Course Panel Survey data, this study investigates the effects of employment on first marriages between 2007 and 2015, including cohorts after the lost generation. The results indicate that: (a) among men who are classed as non-regular employees, unemployed, or low-income regular employees, the likelihood of first marriage is low due to their weak economic position; and (b) women have a low likelihood of first marriage if they are non-regular employees or unemployed, not because of their employment status but because they have less chance of meeting a romantic partner and also because of their values regarding work and marriage. These explicit gender differences in the findings contradict observations made in contemporary Europe and North America, where a trend towards gender convergence in the effects of employment and earnings on marriage has been identified. The ambivalence towards gender equality in family and the workplace will be discussed to understand why many young Japanese remain single

Solubility of Mixed Lanthanide Hydroxide and Oxide Solid Solutions

The solubilities of different multicomponent lanthanide oxide (Ln₂O₃) solid solutions including binary (Ln₁ and Ln₂ = La, Nd, Eu, or Tm), ternary (Ln₁, Ln₂, and Ln₃ = La, Nd, Eu, or Tm), and higher systems (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) were studied after aging for four weeks at 60°C. Our recent study revealed that the phase transformations in binary ((La, Nd) and (La, Eu)) and ternary (La, Nd, Eu) systems are responsible for the formation of (La, Nd)(OH)₃, (La, Eu)(OH)₃, and (La, Nd, Eu)(OH)₃ solid solutions, respectively. The variations in the mole fractions of La³⁺, Nd³⁺, and Eu³⁺ in the sample solutions of these hydroxide solid solutions indicated that a thermodynamic equilibrium might account for the apparent La, Nd, and Eu solubilities. Conversely, the binary and ternary systems containing Tm₂O₃ as the heavy lanthanide oxide retained the oxide-based solid solutions, and their solubility behaviors were dominated by their congruent dissolutions. In the higher multicomponent system, the X-ray diffraction patterns of the solid phases, before and after contact with the aqueous phase indicated the formation of a stable oxide solid solution and their solubility behavior was explained by its congruent dissolution