The “marginal materials” of the river tiber valley—Italy

The building of extensive road networks involves, amongst other things, the need for large amounts of building materials, which must meet special requirements such as quality, quantity and ready availability. Now, however, there is a growing need for alternative or complementary building materials, i.e. of “marginal materials” which are generally easily found very close to large cities. In Latium, and above all in the surroundings of Rome, such marginal materials are being considered for road building in replacement of the traditional “Roman puzzolanas” and alluvial sands that are no longer easily available owing to depletion of sources and to restrictions of various types. This study presents the physico-mechanical characteristics of marginal materials, pointing to the technological processes that may enhance their technical qualities thus making them eligible for replacing traditional materials.     

Molecular dynamics study of a monomeric heme undecapeptide of cytochromec

Summary Molecular dynamics simulations were performed to predict the structure of the monomeric heme-containing peptide microperoxidase-11 (MP-11). The simulations were carried out both in vacuo and in water solvent, taking as starting coordinates those of the corresponding amino acid sequence in the crystal structure of cytochrome c, since the crystallographic structure of MP-11 is not known. The structural data, including the H-bond network, are reported and visualised with the aid of graphical tools. The structure predicted is consistent with what is known experimentally on MP-11. This agreement suggests that molecular dynamics simulations might be useful in the prediction of the catalytic activity or reactivity of microperoxidases.     

Experimental study on anchored bars in R.C. elements with transverse reinforcement

In the present paper, the experimental results of pullout tests on anchorages are presented. The experiments allow for the evaluation of bar-to-concrete slip and splitting crack openings at several points along the anchored bar. Particular attention is devoted to the confining contribution of both transverse reinforcement and concrete cover. Two series of tests have been performed: in the first series, the influence of the confining contribution of transverse bars is studied, while in the second series the confining contribution of the concrete cover is analyzed. In specimens from the first series without transverse reinforcement, a splitting collapse of the anchorage occurred at the onset of the slip at the unloaded end of the anchored bar. The opposite was true for all the other specimens, as the transverse reinforcement percentage was such that a pull-out failure of the anchorage occurred. As the stirrup index of confinement Ω rose, the resultant ultimate bond stress value $\bar \tau $ increased; however, beyond the value Ω_max ≈ 0.05, there was no further significant increase of bond strength. The splitting-crack propagation rate exhibited a bilinear trend, with a faster crack propagation when the load was larger than 50% of the peak load.     

Guest introduction: Some Italian research on real-time systems

This work was partially supported by the Progetto Finalizzato Sistemi Informatici e Calleolo Parallelo of the CNR under grant no. 89.0052.699.     

A proposal for statistical evaluation of the detection of gunshot residues on a suspect

The possibility of accidental contamination of a suspect by gunshot residues (GSRs) is considered. If two hypotheses are taken into account ("the suspect has shot a firearm" and "the suspect has not shot a firearm"), the likelihood ratio of the conditional probabilities of finding a number n of GSRs is defined. Choosing two Poisson distributions, the parameter lambda of the first one coincides with the mean number of GSRs that can be found on a firearm shooter, while the parameter mu of the second one is the mean number of GSRs that can be found on a nonshooter. In this scenario, the likelihood ratio of the conditional probabilities of finding a number n of GSRs in the two hypotheses can be easily calculated. The evaluation of the two parameters lambda and mu and of the goodness of the two probability distributions is performed by using different sets of data: "exclusive" lead-antimony-barium GSRs have been detected in two populations of 31 and 28 police officers at diverse fixed times since firearm practice, and in a population of 81 police officers who stated that they had not handled firearms for almost 1 month. The results show that the Poisson distributions well fit the data for both shooters and nonshooters, and that the probability of detection of two or more GSRs is normally greater if the suspect has shot firearms.     

A semi-automatic system for segmentation of cardiac M-mode images

Pixel classifiers are often adopted in pattern recognition as a suitable method for image segmentation. A common approach to the performance evaluation of classifier systems is based on the measurement of the classification errors and, at the same time, on the computational time. In general, multiclassifiers have proven to be more precise in the classification in many applications, but at the cost of a higher computational load. This paper analyzes different classifiers and proposes an evaluation of the classifiers in the case of semi-automatic processes with human interaction. Medical imaging is a typical application, where automatic or semi-automatic segmentation can be a valuable support to the diagnosis. The paper focuses on the segmentation of cardiac images of fruit flies (genetic model for analyzing human heart’s diseases). Analysis is based on M-modes, that are gray-level images derived from mono-dimensional projections of the video frames on a line. Segmentation of the M-mode images is provided by classifiers and integrated in a multiclassifier. A neural network classifier, a Bayesian classifier, and a classifier based on hidden Markov chains are joined by means of a Behavior Knowledge Space fusion rule. The comparative evaluation is discussed in terms of both accuracy and required time, in which the time to correct the classifier errors by means of human intervention is also taken into account.

Applying a systems thinking framework to assess knowledge assets dynamics for business performance improvement

Knowledge assets represent strategic resources and sources of organizational value creation. Their effective development and deployment is at the basis of organizational value creation capacity. However there is still a lack of applied approaches and tools explaining how knowledge assets dynamics take place in organizational value creation mechanisms. In particular, there is a managerial need to define decision-support frameworks that can enable managers to understand how knowledge assets interact each other and with organizational performance in order to support the achievement of company’s strategic objectives. A better understanding of why and how knowledge assets management initiatives can be turned into value creation mechanisms with positive impacts on business performance is fundamental to avoid misallocation of resources and to support management decisions.This paper proposes a systems thinking-based framework, the Knowledge Assets Dynamics Value Map (KAVDM), to explicate the working mechanisms by means knowledge assets can evolve on the basis of knowledge management initiatives and affect business performance improvements. The KAVDM offers a holistic view of the mechanisms at the basis of how knowledge assets are translated into organizational value. It supports the explanation and monitoring of how knowledge assets are interpedently and dependently linked, and how the management of one knowledge asset activates flow dynamics, that influence both other knowledge assets and business performance. Using the KAVDM managers can reflect upon the knowledge components grounding a company’s value creation and assess their mental models and views of the reality. Finally, an application of the KAVDM within a construction company is presented and its main managerial benefits addressed.     

A virtual sensor for backlash in robotic manipulators

Journal of Intelligent Manufacturing - Gear backlash is a quite serious problem in industrial robots, it causes vibrations and impairs the robot positioning accuracy. Backlash estimation allows...     

Unknown-state, unknown-input reconstruction in discrete-time nonminimum-phase systems: Geometric methods

The complete solution to the unknown-state, unknown-input reconstruction problem in systems with invariant zeros is inherently conditioned by the fact that, for any invariant zero, at least one initial state exists, such that the output is not affected when the mode of the invariant zero is properly injected into the system. Despite this intrinsic limitation, the problem of reconstructing the initial state and the inaccessible inputs from the available measurements has recently attracted remarkable interest, owing to its impact on the synthesis of enhanced-reliability control systems. This contribution consists of a geometric method which solves the unknown-state, unknown-input reconstruction problem in discrete-time systems with invariant zeros anywhere in the complex plane, except the unit circumference. The case of systems with the invariant zeros in the open set outside the unit disc is regarded as the basic one. The difficulties related to the presence of those invariant zeros are overcome by accepting a reconstruction delay commensurate to the invariant zero time constants and the accuracy required for reconstruction. The solution devised for that case also applies to systems without invariant zeros. However, in this case, reconstruction is exact and the delay depends on the number of iterations needed for a certain conditioned invariant algorithm to converge. Finally, the more general case of systems with invariant zeros lying anywhere in the complex plane, with the sole exception of the unit circumference, is reduced to the fundamental one through the synthesis of an appropriate filter.     

Multi-scale simulations of plasma with iPIC3D

The implicit Particle-in-Cell method for the computer simulation of plasma, and its implementation in a three-dimensional parallel code, called iPIC3D, are presented. The implicit integration in time of the Vlasov–Maxwell system, removes the numerical stability constraints and it enables kinetic plasma simulations at magnetohydrodynamics time scales. Simulations of magnetic reconnection in plasma are presented to show the effectiveness of the algorithm.