On velocity-based local model networks for nonlinear identification

This paper exposes the strengths and weaknesses of the recently proposed velocity-based local model (LM) network. The global dynamics of the velocity-based blended representation are directly related to the dynamics of the underlying local models, an important property in the design of local controller networks. Furthermore, the sub-models are continuous-time and linear providing continuity with established linear theory and methods. This is not true for the conventional LM framework, where the global dynamics are only weakly related to the affine sub-models. In this paper, a velocity-based multiple model network is identified for a highly nonlinear dynamical system. The results show excellent dynamical modelling performances, highlighting the value of the velocity-based approach for the design and analysis of LM based control. Three important practical issues are also addressed. These relate to the blending of the velocity-based local models, the use of normalised Gaussian basis functions and the requirement of an input derivative.

Reduced-size polarized basis sets for calculations of molecular electric properties. III. Second-row atoms

Reduced-size polarized (ZmPolX) basis sets are developed for the second-row atoms X = Si, P, S, and Cl. The generation of these basis sets follows from a simple physical model of the polarization effect of the external electric field which leads to highly compact polarization functions to be added to the chosen initial basis set. The performance of the ZmPolX sets has been investigated in calculations of molecular dipole moments and polarizabilities. Only a small deterioration of the quality of the calculated molecular electric properties has been found. Simultaneously the size of the present reduced-size ZmPolX basis sets is about one-third smaller than that of the usual polarized (PolX) sets. This reduction considerably widens the range of applications of the ZmPolX sets in calculations of molecular dipole moments, dipole polarizabilities, and related properties.

Structural basis of substrate selectivity in the glycerol-3-phosphate: phosphate antiporter GlpT.

Major facilitators represent the largest superfamily of secondary active transporter proteins and catalyze the transport of an enormous variety of small solute molecules across biological membranes. However, individual superfamily members, although they may be architecturally similar, exhibit strict specificity toward the substrates they transport. The structural basis of this specificity is poorly understood. A member of the major facilitator superfamily is the glycerol-3-phosphate (G3P) transporter (GlpT) from the Escherichia coli inner membrane. GlpT is an antiporter that transports G3P into the cell in exchange for inorganic phosphate (Pi). By combining large-scale molecular-dynamics simulations, mutagenesis, substrate-binding affinity, and transport activity assays on GlpT, we were able to identify key amino acid residues that confer substrate specificity upon this protein. Our studies suggest that only a few amino acid residues that line the transporter lumen act as specificity determinants. Whereas R45, K80, H165, and, to a lesser extent Y38, Y42, and Y76 contribute to recognition of both free Pi and the phosphate moiety of G3P, the residues N162, Y266, and Y393 function in recognition of only the glycerol moiety of G3P. It is the latter interactions that give the transporter a higher affinity to G3P over Pi.

La visión artificial, un nuevo aliado para el análisis de imágenes artísticas

En este estudio se evalúa el rendimiento de los métodos de Bag-of-Visualterms (BOV) para la clasificación automática de imágenes digitales de la base de datos del artista Miquel Planas. Estas imágenes intervienen en la ideación y diseño de su producción escultórica. Constituye un interesante desafío dada la dificultad de la categorización de escenas cuando éstas difieren más por los contenidos semánticos que por los objetos que contienen. Hemos empleado un método de reconocimiento basado en Kernels introducido por Lazebnik, Schmid y Ponce en 2006. Los resultados son prometedores, en promedio, la puntuación del rendimiento es aproximadamente del 70%. Los experimentos sugieren que la categorización automática de imágenes basada en métodos de visión artificial puede proporcionar principios objetivos en la catalogación de imágenes y que los resultados obtenidos pueden ser aplicados en diferentes campos de la creación artística.

Becoming private property: custom, law, and the geographies of ‘ownership’ in 18th- and 19th-century England

The making private of hitherto public goods is a central tenet of neoliberalism. From land in Africa, Asia, and South America to the assertion of property rights over genes and cells by corporations, the process(es) of making private property matters more than ever. And yet, despite this importance, we know remarkably little about the spatial plays through which things become private property. In this paper I seek to address this imbalance by focusing upon the formative context of 18th- and early-19th-century England. The specific lens is wood, that most critical of all ‘natural’ things other than land in the transition to market-driven economies. It is shown that the interplay between custom, law, and local practices rendered stable and aspatial definitions of property impossible. Whilst law was the key technology through which property was mediated, the cadence of particular places gave these mediations distinctive forms. I conclude that not only must we take property seriously, but we must also take the conditions and contexts of its making seriously too.

Structure-Property Relationships in Biaxially Deformed Polypropylene Nanocomposites

Semi-solid forming processes such as thermoforming and injection blow moulding are used to make much of today’s packaging. As for most packaging there is a drive to reduce product weight and improve properties such as barrier performance. Polymer nanocomposites offer the possibility of increased modulus
(and hence potential product light weighting) as well as improved barrier properties and are the subject of much research attention. In this particular study, polypropylene–clay nanocomposite sheets produced via biaxial deformation are investigated and the structure of the nanocomposites is quantitatively determined in order to gain a better understanding of the influence of the composite structure on mechanical properties. Compression moulded sheets of polypropylene and polypropylene/Cloisite 15A nanocomposite (5 wt.%) were biaxially stretched to different stretching ratios, and then the structure of
the nanocomposite was examined using XRD and TEM techniques. Different stretching ratios produced different degrees of exfoliation and orientation of the clay tactoids. The sheet properties were then investigated using DSC, DMTA, and tensile tests .It was found that regardless of the degree of exfoliation or
orientation, the addition of clay has no effect on percentage crystallinity or melting temperature, but it has an effect on the crystallization temperature and on the crystal size distribution. DMTA and tensile tests show that both the degree of exfoliation and the degree of orientation positively correlate with the dynamic mechanical properties and the tensile properties of the sheet.