Fault-free longest paths in star networks with conditional link faults

AbstractThe star network, which belongs to the class of Cayley graphs, is one of the most versatile interconnection networks for parallel and distributed computing. In this paper, adopting the conditional fault model in which each node is assumed to be incident with two or more fault-free links, we show that an n-dimensional star network can tolerate up to 2n−7 link faults, and be strongly (fault-free) Hamiltonian laceable, where n≥4. In other words, we can embed a fault-free linear array of length n!−1 (n!−2) in an n-dimensional star network with up to 2n−7 link faults, if the two end nodes belong to different partite sets (the same partite set). The result is optimal with respect to the number of link faults tolerated. It is already known that under the random fault model, an n-dimensional star network can tolerate up to n−3 faulty links and be strongly Hamiltonian laceable, for n≥3

Structural study in Highly Compressed BiFeO3 Epitaxial Thin Films on YAlO3

We report a study on the thermodynamic stability and structure analysis of the epitaxial BiFeO3 (BFO) thin films grown on YAlO3 (YAO) substrate. First we observe a phase transition of MC-MA-T occurs in thin sample (<60 nm) with an utter tetragonal-like phase (denoted as MII here) with a large c/a ratio (~1.23). Specifically, MII phase transition process refers to the structural evolution from a monoclinic MC structure at room temperature to a monoclinic MA at higher temperature (150oC) and eventually to a presence of nearly tetragonal structure above 275oC. This phase transition is further confirmed by the piezoforce microscopy measurement, which shows the rotation of polarization axis during the phase transition. A systematic study on structural evolution with thickness to elucidate the impact of strain state is performed. We note that the YAO substrate can serve as a felicitous base for growing T-like BFO because this phase stably exists in very thick film. Thick BFO films grown on YAO substrate exhibit a typical "morphotropic-phase-boundary"-like feature with coexisting multiple phases (MII, MI, and R) and a periodic stripe-like topography. A discrepancy of arrayed stripe morphology in different direction on YAO substrate due to the anisotropic strain suggests a possibility to tune the MPB-like region. Our study provides more insights to understand the strain mediated phase co-existence in multiferroic BFO system.Comment: 18 pages, 6 figures, submitted to Journal of Applied Physic

Demonstration of the Interaction between Two Stopped Light Pulses

We report the first experimental demonstration that two light pulses were made motionless and interacted with each other via a medium. The interaction time is, in principle, as long as possible and a considerable efficiency can be achieved even below single-photon level. We utilized the optical process of one photon pulse switched by another based on the effect of electromagnetically induced transparency to demonstrate the enhancement of optical nonlinear efficiency. With moving light pulses, the switching is activated at energy per area of 2 photons per atomic absorption cross section in the best situation as discussed in [Phys. Rev. Lett. 82, 4611 (1999)]. With motionless light pulses, we demonstrated that the switching is activated at 0.56 photons per atomic absorption cross section and that the light level can be further reduced by increasing the optical density of the medium. Our work enters a new regime of low light physics.Comment: 7 pages, 5 figure

Competitive Retailer Strategies for New Market Research, Entry and Positioning Decisions

This paper investigates strategies for new market research and positioning of stores or products by competing retailers in a duopoly setting. We examine the scenario where the two retailers are considering entry into an uncertain new market that is an extension of their existing markets. The retailers must make decisions on whether or not to first conduct research about the new market\u27s location relative to their existing markets and its size before deciding on their own positioning in it. We first study a sequential-move leader–follower setup to highlight the choice of an “innovate-or-imitate” strategy. We find when the potential new market is small, neither retailer is adequately incentivized to do research to acquire information about the new market. As the size of the new market increases, the follower is induced to do such research. When the new market is very sizable, the leader conducts research and knows the new market\u27s location while the follower free-rides. We then examine a simultaneous-move setup, in which one retailer might decide against acquiring new market information even when the cost of doing so is low. We further observe that differentiation (e.g., in terms of products or store locations) is greater in the simultaneous-move setup than in the sequential setup

Recent Chinese Migrants in small Towns of Post-apartheid South Africa

South Africa is host to the largest population of Chinese on the African continent, with estimates ranging from 250,000 – 350,000. Various waves of migration from China to South Africa have resulted in the creation of diverse, multi-generational, and multi-lingual communities of Chinese. The article explores these waves of migration and then focuses on the newest Chinese migrants, mostly from rural parts of Fujian province, many of whom are settling in small, rural towns across the country. The authors conclude with an attempt to position these newest Chinese migrants in terms of race, class, and power and examine the similarities and differences between them and other migrant communities elsewhere.L’Afrique du sud accueille la plus importante population chinoise du continent africain, estimée entre 250 000 et 300 000 personnes. Les différentes vagues migratoires chinoises ont créé des communautés chinoises diverses, pluri-générationnelles et plurilingues. Cet article analyse ces vagues migratoires et s’intéresse plus particulièrement aux nouveaux migrants chinois pour la plupart originaires des zones rurales du Fujian et principalement établis dans les petites villes rurales sud-africaines. Puis les auteurs analysent ces nouveaux migrants en termes de race, classe et pouvoir et examinent ce qui les rapprochent et les différencient des autres communautés migrantes.Sudáfrica acoge población china la más importante del continente africano, que se estima entre 250 000 y 300 000 personas. Las diferentes olas de migración chinas han creado varias comunidades chinas, multi-generacionales y plurilingüees. Este artículo analiza estas olas de migración y se interesa particularmente por los nuevos migrantes chinos oriundos, en su mayoría, de zonas rurales de Fujian y que se encuentran principalmente en pequeñas ciudades rurales sudafricanas. Después, los autores analizan estos nuevos migrantes en términos de raza, clase, poder y examinan lo que le acerca o le diferencia de las otras comunidades inmigradas