The online Prize-Collecting Traveling Salesman Problem

We study the online version of the Prize-Collecting Traveling Salesman Problem (PCTSP), a generalization of the Traveling Salesman Problem (TSP). In the TSP, the salesman has to visit a set of cities while minimizing the length of the overall tour. In the PCTSP, each city has a given weight and penalty, and the goal is to collect a given quota of the weights of the cities while minimizing the length of the tour plus the penalties of the cities not in the tour. In the online version, cities are disclosed over time. We give a 7/3-competitive algorithm for the problem, which compares with a lower bound of 2 on the competitive ratio of any deterministic algorithm. We also show how our approach can be combined with an approximation algorithm in order to obtain an O(1)-competitive algorithm that runs in polynomial time.     

The effect of an innovative atmospheric plasma jet treatment on physical and mechanical properties of wool fabrics

This work concerns the study of some important physical and mechanical properties of a wool fabric treated with a roll-to-roll atmospheric plasma jet equipment. The plasma pilot unit, based on a post-discharge technology, was equipped with an innovative plasma-to-fabric contactor, which promotes a relevant penetration of plasma through the fabric structure and geometrically defines the atmosphere. Wool fabrics were processed at three different velocities (1, 3 and 6 m/min); the other process variables were kept constant. Tensile strength, elongation at break, surface thickness, wettability and air permeability increased after the plasma treatment, while several low-stress mechanical properties, strictly related to the handle, were not modified. SEM analysis was also carried out to better interpret the above macroscopic results.     

Sensitivity analysis for fixed-priority real-time systems

At early stages in the design of real-time embedded applications, the timing attributes of the computational activities are often incompletely specified or subject to changes. Later in the development cycle, schedulability analysis can be used to check the feasibility of the task set. However, the knowledge of the worst-case response times of tasks is often not sufficient to precisely determine the actions that would correct a non-schedulable design. In these situations, sensitivity analysis provides useful information for changing the implementation, by giving a measure of those computation times that must be reduced to achieve feasibility, or those that can be increased in case of a product extension, or providing the range of feasible periods for selecting the proper task activation rates. In this work, we exploit the concept of feasibility region to propose a faster and more concise solution to the sensitivity analysis problem with respect to existing techniques based on binary search. Furthermore, we show how the formalization of other problems in the feasibility domain, such as managing overloads through elastic scheduling, can be extended to the exact analysis.     

Hemispheric memories for the content and position of food caches in the domestic chick.

From Day 2 to Day 4 of life, chicks were fed daily in a large enclosure with 2 identical food caches, each filled with a different type of seed. On Day 5, binocular and monocular chicks were fed in their home cages 1 type of seed exclusively for 30 min. At test, soon after this devaluation phase, both binocular and right-eyed chicks chose the food caches containing the seeds that had not been devalued; in contrast, left-eyed chicks did not show a clear choice. Experiments revealed that the asymmetry was not due to lack of motivation, worse spatial memory, or inability to remember the consequences of devaluation by left-eyed chicks. Results suggest that young chicks can form declarative-like memories of the content of food caches. However, chicks using their left eye (which provides a supply of mainly to the right hemisphere) failed to integrate memory of the content of food caches with memory of the consequences of devaluation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modelling waveguiding photonic bandgap structures by leaky modepropagation method

A model of one-dimensional fully etched waveguiding photonic bandgap (FWPBG) structures, based on the leaky mode propagation (LMP) method, is proposed for the first time, to perform a complete analysis of the propagating characteristics including the radiation loss for a structure of finite extension     

Increase of trans-resveratrol in typical Sicilian wine using β-Glucosidase from various sources

β-Glucosidase (EC 3.2.1.21) (β-G) from different sources were tested to increase the trans-resveratrol in some Sicilian wines by hydrolysing resveratrol glucoside. β-G from Aspergillus niger mould was tested as a crude and purified enzyme, and compared with the same enzyme from Saccharomyces cerevisiae yeast. Specific purification served to eliminate collateral enzyme activities so that β-G could be used simply and economically. Aspergillus niger β-G produced trans-resveratrol increases of up to 75%, with no change in physico-chemical properties and bouquet, and an increase in health and nutritional properties. S. cerevisiae β-G raised free-terpenol levels, but impaired wine colour due to anthocyanase activity.     

Analytical approach for thermal and electrical design of multilayerstructure integrated devices

An analytical method for the electrothermal design of multilayer structure integrated devices is presented. It can be easily applied to a large variety of devices and is independent of the specific physical properties of the layers, also accounting for the temperature dependence of the thermal conductivity     

Present status of the theory of electron beam instabilities in storage rings

The coherent beam instabilities in circular accelerators are explained in terms of simple concepts of feedback devices. The notion of coupling impedance is introduced and interpreted by means of engineering circuit analysis. The condition of stability for the coherent motion is given in terms of the coupling impedance and accelerator and beam parameters.