Dependencies and Simultaneity in Membrane Systems

Membrane system computations proceed in a synchronous fashion: at each step all the applicable rules are actually applied. Hence each step depends on the previous one. This coarse view can be refined by looking at the dependencies among rule occurrences, by recording, for an object, which was the a rule that produced it and subsequently (in a later step), which was the a rule that consumed it. In this paper we propose a way to look also at the other main ingredient in membrane system computations, namely the simultaneity in the rule applications. This is achieved using zero-safe nets that allows to synchronize transitions, i.e., rule occurrences. Zero-safe nets can be unfolded into occurrence nets in a classical way, and to this unfolding an event structure can be associated. The capability of capturing simultaneity of zero-safe nets is transferred on the level of event structure by adding a way to express which events occur simultaneously

A note on two notions of compliance

We establish a relation between two models of contracts: binary session types, and a model based on event structures and game-theoretic notions. In particular, we show that compliance in session types corresponds to the existence of certain winning strategies in game-based contracts.Comment: In Proceedings ICE 2014, arXiv:1410.701

A new operational representation of dependencies in Event Structures

The execution of an event in a complex and distributed system where the dependencies vary during the evolution of the system can be represented in many ways, and one of them is to use Context-Dependent Event structures. Event structures are related to Petri nets. The aim of this paper is to propose what can be the appropriate kind of Petri net corresponding to Context-Dependent Event structures, giving an operational flavour to the dependencies represented in a Context/Dependent Event structure. Dependencies are often operationally represented, in Petri nets, by tokens produced by activities and consumed by others. Here we shift the perspective using contextual arcs to characterize what has happened so far and in this way to describe the dependencies among the various activities

Measurement of deformation gradients in hot rolling of AA3004

In this paper we describe an experimental technique developed to measure the deformation gradients and temperature in a single hot rolling pass of an AA3004 sample that was fitted with an insert. The insert had been previously hand engraved with a 1 × 1 mm grid pitch, and the analysis of the data digitally captured from the image of the deformed grid enabled the calculation of the components of the deformation gradient tensor. Four steel pins prevented relative motion between the insert and the rest of the sample. No detachment was observed between insert and sample after rolling. The temperature was measured during rolling using two embedded thermocouples, one close to the surface and the other in the centerline. The commercial finite element code ABAQUS was used to create a three-dimensional model of the rolling process. The recorded temperature was compared to the numerical values evaluated after tuning the heat transfer coefficient. The shape of the grid after rolling was checked against the deformed mesh using different friction coefficients in order to obtain the optimum match. The unusually large length of the insert enabled the rolling process to be stopped halfway so that a picture of the roll-gap area could be obtained. This provided a partially deformed grid that represented the transient state during rolling. The experimentally determined deformation gradient in this area as well as in the steady-state area agreed well with the finite element predictions. © 2005 Society for Experimental Mechanics

Student’s Co-Creation Behavior in a Business and Economic Bachelor’s Degree in Italy: Influence of Perceived Service Quality, Institutional Image, and Loyalty

Universities play a significant role in the economic development of society as they pro- vide knowledge and skills that are essential for social sustainability. In recent years, universities shifted their focus towards student-centered education and need to reconsider their sustainable strategies to become more competitive by encouraging student co-creation behaviors. To create a unique experience, universities aim to involve students in creating and delivering their educational experiences. The purpose of this paper is to investigate how the perceived quality of educational service and the institutional image of a university influence students’ value co-creation behavior, and the role of loyalty in this process. The study is based on two complementary studies conducted in an Italian public university. The first study involved 720 undergraduate students with one business management bachelor’s degree who completed a questionnaire to collect primary data. The second study used six focus groups to identify which specific students’ experiences and university activities stimulated co-creation behaviors. The results show that student loyalty plays an important mediating role between university image, students’ quality perception, and co-creation behavior. Additionally, only three dimensions of quality, namely quality non-academy aspects, quality reputation, and quality access have an impact on students’ loyalty. Therefore, only two dimensions of brand image, university brand knowledge (UK), and university brand prestige (UPR) have a direct effect on value co-creation behavior. These findings have important implications for higher education institutions (HEIs) to develop managerial strategies that increase students’ co-creation behavior. The co-creation process should be considered as part of HEIs’ image-building and quality policy-enhancing strategy. Despite the value co-creation approach being overlooked in studies on HEIs governance, this study highlights its potential as a strategic approach for improving service quality and university image

Leave-one-out prediction error of systolic arterial pressure time series under paced breathing

In this paper we show that different physiological states and pathological conditions may be characterized in terms of predictability of time series signals from the underlying biological system. In particular we consider systolic arterial pressure time series from healthy subjects and Chronic Heart Failure patients, undergoing paced respiration. We model time series by the regularized least squares approach and quantify predictability by the leave-one-out error. We find that the entrainment mechanism connected to paced breath, that renders the arterial blood pressure signal more regular, thus more predictable, is less effective in patients, and this effect correlates with the seriousness of the heart failure. The leave-one-out error separates controls from patients and, when all orders of nonlinearity are taken into account, alive patients from patients for which cardiac death occurred

La Meccanizzazione della raccolta del mirto

The plant of the myrtle in past has been always considered one marginal cultivation and of insufficient interest. Only in the last five years it has been knowledge the economic importance for the demanded crescent of liquor of myrtle, product up to now nearly exclusively in Sardinia. Therefore, new sensibility has been developed one and a greater knowledge of the importance of a deepened study more of the cultivation from the biological point of view and the point of view of one rations mechanized harvester of the berries. The aim of the work was that one to characterize an harvester of the berries from the plant, avoiding the damaging of the plant and above all of the fruits that influenced on the quality of the finished product. In this present study they are evidences the comparison between some tests of harvest in turn to obtained and carried out with two different types of harvesters some in relation to the ransom of the plants

Effect of different pastures on CLA content in milk and sheep cheese

It is known that milk composition included conjugated linoleic acid (CLA) is affected by animal feeding system (Cabiddu et al., 2001). In Sardinia dairy sheep feeding is mainly based on pastures. Most of them are characterised by self-regenerating species, like annual ryegrass (Lolium rigidum Gaudin) and burr medic (Medicago polymorpha L.). Non conventional species belonging to the Compositae family such as (Chrysanthemum coronarium L.) seem interesting for sheep feeding when other herbages decrease in quality (late spring- early summer). It was observed that C. coronarium establishes rapidly, can be grazed early in the growing season and persist where other pasture species may disappear; for these reasons it can be considered a valuable source of food. Moreover a preliminary study with dairy sheep fed fresh forage of C. coronarium showed relatively high levels of CLA in milk (Molle G. pers. com.) The aim of the present work was to study the influence of different pastures on milk composition, with particular reference to CLA and its precursors

A SIMULATION TOOL ASSISTING THE DESIGN OF A CLOSE RANGE PHOTOGRAMMETRY SYSTEM FOR THE SARDINIA RADIO TELESCOPE

The Sardinia Radio Telescope (SRT) is a 64 m diameter antenna, whose primary mirror is equipped with an active surface capable to correct its deformations by means of a thick network of actuators. Close range photogrammetry (CRP) was used to measure the self-load deformations of the SRT primary reflector from its optimal shape, which are requested to be minimized for the radio telescope to operate at full efficiency. In the attempt to achieve such performance, we conceived a near real-time CRP system which requires the cameras to be installed in fixed positions and at the same time to avoid any interference with the antenna operativeness. The design of such system is not a trivial task, and to assist our decision we therefore developed a simulation pipeline to realistically reproduce and evaluate photogrammetric surveys of large structures. The described simulation environment consists of (i) a detailed description of the SRT model, included the measurement points and the camera parameters, (ii) a tool capable of generating realistic images accordingly to the above model, and (iii) a self-calibrating bundle adjustment to evaluate the performance in terms of RMSE of the camera configurations