Ship design optimization in the multimodal logistics framework

The significance of multimodal transportation systems has worldwide increased significantly over the past two decades. European Union, United States and Japan have increased their efforts in studying the dynamics of multimodal transportation networks. In the paper about recent research work on the optimization problem of the design of ferries and Ro-Ro cargo ships using pattern recognition techniques (Artificial Neural Networks), Multi-objective Genetic Algorithms (MOGA) and the know-how created through the EU FP6 Research Project LOGBASED. A case study on the transportation of agricultural goods from the Greek Island of Crete to the markets of Munich is presented. The results of this study prove useful for the assessment of viable solutions serving in a balanced way for the interests of shipyards, ship operators, cargo owners, banking and financial institutions, investors and government administrations in the framework of optimized transportation scenarios

Does the CAMELS bank ratings system follow a procyclical pattern?

The financial crisis which erupted in 2007-8 has illustrated the disruptive effects of procyclicality. The phenomenon of procyclicality refers to the mutually reinforcing interactions between the financial system and the real economy that tend to amplify business cycle fluctuations. In this study, we empirically investigate the sensitivity of the CAMELS ratings system, which is used by the U.S. authorities to monitor the conditions in the banking market, to the fluctuations of the economic cycle. Our results suggest that the overall state of the U.S. economy and bank regulatory ratings are positively linked to each other: CAMELS increase during economic upturns and decrease during downturns. This is to say that the performance and risk-taking behaviour of banks is rated higher when the conditions in the economy are favourable and lower when the economic environment is weak. Along these lines, we document a positive relationship between CAMELS and the conditions in financial markets. This very important and rather unknown source of procyclicality should be taken into serious consideration by authorities

Topological phases and topological entropy of two-dimensional systems with finite correlation length

We elucidate the topological features of the entanglement entropy of a region in two dimensional quantum systems in a topological phase with a finite correlation length $\xi$. Firstly, we suggest that simpler reduced quantities, related to the von Neumann entropy, could be defined to compute the topological entropy. We use our methods to compute the entanglement entropy for the ground state wave function of a quantum eight-vertex model in its topological phase, and show that a finite correlation length adds corrections of the same order as the topological entropy which come from sharp features of the boundary of the region under study. We also calculate the topological entropy for the ground state of the quantum dimer model on a triangular lattice by using a mapping to a loop model. The topological entropy of the state is determined by loop configurations with a non-trivial winding number around the region under study. Finally, we consider extensions of the Kitaev wave function, which incorporate the effects of electric and magnetic charge fluctuations, and use it to investigate the stability of the topological phase by calculating the topological entropy.Comment: 17 pages, 4 figures, published versio

How to develop a meaningful radiomic signature for clinical use in oncologic patients.

During the last decade, there is an increasing usage of quantitative methods in Radiology in an effort to reduce the diagnostic variability associated with a subjective manner of radiological interpretation. Combined approaches where visual assessment made by the radiologist is augmented by quantitative imaging biomarkers are gaining attention. Advances in machine learning resulted in the rise of radiomics that is a new methodology referring to the extraction of quantitative information from medical images. Radiomics are based on the development of computational models, referred to as "Radiomic Signatures", trying to address either unmet clinical needs, mostly in the field of oncologic imaging, or to compare radiomics performance with that of radiologists. However, to explore this new technology, initial publications did not consider best practices in the field of machine learning resulting in publications with questionable clinical value. In this paper, our effort was concentrated on how to avoid methodological mistakes and consider critical issues in the workflow of the development of clinically meaningful radiomic signatures

Ballistic Spin Injection from Fe into ZnSe and GaAs with a (001), (111), and (110) orientation

We present first-principles calculations of ballistic spin injection in Fe/GaAs and Fe/ZnSe junctions with orientation (001), (111), and (110). We find that the symmetry mismatch of the Fe minority-spin states with the semiconductor conduction states can lead to extremely high spin polarization of the current through the (001) interface for hot and thermal injection processes. Such a symmetry mismatch does not exist for the (111) and (110) interfaces, where smaller spin injection efficiencies are found. The presence of interface states is found to lower the current spin polarization, both with and without a Schottky barrier. Finally, a higher bias can also affect the spin injection efficiency.Comment: 12 pages, 18 figure

Electronic States of Graphene Grain Boundaries

We introduce a model for amorphous grain boundaries in graphene, and find that stable structures can exist along the boundary that are responsible for local density of states enhancements both at zero and finite (~0.5 eV) energies. Such zero energy peaks in particular were identified in STS measurements [J. \v{C}ervenka, M. I. Katsnelson, and C. F. J. Flipse, Nature Physics 5, 840 (2009)], but are not present in the simplest pentagon-heptagon dislocation array model [O. V. Yazyev and S. G. Louie, Physical Review B 81, 195420 (2010)]. We consider the low energy continuum theory of arrays of dislocations in graphene and show that it predicts localized zero energy states. Since the continuum theory is based on an idealized lattice scale physics it is a priori not literally applicable. However, we identify stable dislocation cores, different from the pentagon-heptagon pairs, that do carry zero energy states. These might be responsible for the enhanced magnetism seen experimentally at graphite grain boundaries.Comment: 10 pages, 4 figures, submitted to Physical Review