The Structure of the Interbank Market in Kenya

This chapter discusses the evolution of the network structure of Kenya’s overnight market. It applies several measurements derived from network theory to uncover some key microstructure characteristics and the nature of the interbank market segmentation. An important issue is to understand what opportunities and challenges the structure of the interbank network presents for liquidity management and stability of the banking system. The results reveal a fragmented market, consisting of local clusters with hub-like and periphery banks. These features seem to become more prominent with time. Although the interbank structure is largely incomplete (density of about 0.25), each bank can be linked to all other banks in the network in no more than three steps. While this may imply that the core potentially provides an efficient shortcut for most peripheral banks for accessing liquidity in the network, the short-path length suggests that contagion can also spread with ease.

Rain attenuation statistics over 5G millimetre wave links in Malaysia

<p>Millimetre wave band is a solid contender to be utilized for the future 5G wireless systems deployment. Rain-induced attenuation is a major disadvantage at these frequencies. This paper presents statistics of rain-induced attenuation and rainfall data for two years of horizontally polarized links propagating at 38 GHz and 26 GHz over a terrestrial path link of 301 meters. From the analysed datasets, a rain rate around 116 mm/h exceeded at 0.01% of the time of an average year, while the links recorded 16 and 9.5 dB at the same percentage of time for 38 and 26 GHz respectively. The study aims to identify the prediction model that deliver most reasonable predictions for 5G links operating in Malaysian tropical climate. ITU-R P.530-17, Mello’s, and Ghiani’s models were all examined. Using ITU-R model, relative error margins of around 3.8%, 30% and 49.7% alongside 22.3, 9.5, 33% were obtained in 0.1%, 0.01% and 0.001% of the time for 26 and 38 GHz respectively. Curiously, ITU-R model demonstrates better predictions to measured rain attenuation with lower error probability. This study highlights the need for new prediction models for short path-length 5G links and helps to improve the design of terrestrial links operating at millimetre wave frequencies in tropical regions.</p>

The Structure of Plant-Animal Mutualistic Networks

This chapter discusses the structure of mutualistic networks. Despite their apparent complexity, mutualistic networks show repeated, universal structural patterns independent of species composition, size, and other ecological details. First, mutualistic networks are very heterogeneous: whereas the majority of species have only one or a few interactions, a few species are much more connected than expected by chance. Second, mutualistic networks are highly nested, that is, specialists interact with well-defined subsets of the species generalists interact with. Third, mutualistic networks are built on weak, asymmetric interactions among species. Fourth, mutualistic networks have a strong small-world property; that is, they simultaneously have a short path length among any pair of species and a high clustering coefficient. Finally, these networks are significantly modular—that is, there are small groups of species with morphological convergence of traits that interact strongly among themselves and more loosely with species from other modules. These modules can be regarded as the basic building blocks of mutualistic networks and their coevolutionary units.