The Importance of Human Mental Workload in Web Design

The focus of this study is the introduction of the construct of Human Mental Workload (HMW) in Web design, aimed at supporting current interaction design practices. An experiment has been conducted using the original Wikipedia and Google web-interfaces, and using two slightly different versions. Three subjective psychological mental workload assessment techniques (NASA-TLX, Workload Profile and SWAT) with a well-established assessments usability tool (SUS) have been adopted. T-tests have been performed to study the statistical significance of the original and modified web-pages, in terms of workload required by typical tasks and perceived usability. Preliminary results show that, in one ideal case, increments of usability correspond to decrements of generated workload, confirming the negative impact of the structural changes on the interface. In another case, changes are significant in terms of usability but not in terms of generated workloads, thus raising research questions and underlying the importance of Human Mental Workload in Interaction Design

A Randomized Approach to Space Debris Footprint Characterization

This paper studies the problem of characterizing the 4D (space cross time) region of the airspace that will be occupied by a space debris during an uncontrolled reentry, with the final goal of supporting the air traffic controllers in re-routing the air traffic when such an event occurs. The problem is formulated in terms of a chance-constrained optimization program, which is solved via a simulation-based method. The approach is comparatively evaluated against the so-called covariance propagation method recently proposed in the literature, emphasizing how some of the limitations of the latter method are overcome

The Effect of Long-term Freezing on Renneting Properties of Sarda Sheep Milk

Cold storage is a well-known strategy to limit concerns about seasonality for sheep dairy productions. The aim of this study was to investigate the effect of long-term freezing on milk renneting properties from the Sarda sheep, an autochthonous breed from Italy. Two-hundred milk samples from 50 pluriparous Sarda ewes were collected at monthly intervals throughout the lactation from April to July. Each sample of fresh milk was analysed for composition and subsamples were obtained and frozen for one, three and five months. Renneting properties, both from the fresh and frozen subsamples, were achieved using the Formagraph instrument and results were submitted to a mixed model statistical analysis. The storage effect significantly affected (P<0.01) the renneting parameters. A large amount of non coagulating subsamples was registered after a long-term frozen storage. Furthermore, milk clotting time was longer in frozen subsamples and curd firmness diminished after a freezing period of five months. In conclusion, the remarkable decreasing of sheep milk renneting characteristics after frozen storage can predict a worse yield and quality of cheese-making and suggests that freezing of Sarda raw milk should be limited to shorter periods

The Effect of Long-term Freezing on Renneting Properties of Sarda Sheep Milk

Cold storage is a well-known strategy to limit concerns about seasonality for sheep dairy productions. The aim of this study was to investigate the effect of long-term freezing on milk renneting properties from the Sarda sheep, an autochthonous breed from Italy. Two-hundred milk samples from 50 pluriparous Sarda ewes were collected at monthly intervals throughout the lactation from April to July. Each sample of fresh milk was analysed for composition and subsamples were obtained and frozen for one, three and five months. Renneting properties, both from the fresh and frozen subsamples, were achieved using the Formagraph instrument and results were submitted to a mixed model statistical analysis. The storage effect significantly affected (P<0.01) the renneting parameters. A large amount of non coagulating subsamples was registered after a long-term frozen storage. Furthermore, milk clotting time was longer in frozen subsamples and curd firmness diminished after a freezing period of five months. In conclusion, the remarkable decreasing of sheep milk renneting characteristics after frozen storage can predict a worse yield and quality of cheese-making and suggests that freezing of Sarda raw milk should be limited to shorter periods

A Randomized Approach to Space Debris Footprint Characterization

This paper studies the problem of characterizing the 4D (space cross time) region of the airspace that will be occupied by a space debris during an uncontrolled reentry, with the final goal of supporting the air traffic controllers in re-routing the air traffic when such an event occurs. The problem is formulated in terms of a chance-constrained optimization program, which is solved via a simulation-based method. The approach is comparatively evaluated against the so-called covariance propagation method recently proposed in the literature, emphasizing how some of the limitations of the latter method are overcome

A new hybrid approach using the simultaneous perturbation stochastic approximation method for the optimal allocation of electrical energy storage systems

This paper deals with the optimal allocation (siting and sizing) of distributed electrical energy storage systems in unbalanced electrical distribution systems. This problem is formulated as a mixed, non-linear, constrained minimization problem, in which the objective function involves economic factors and constraints address the technical limitations of both network and distributed resources. The problem is cumbersome from the computational point of view due to the presence of both constraints of an intertemporal nature and a great number of state variables. In order to guarantee reasonable accuracy-although limiting the computational efforts-a new approach is proposed in this paper: it is based on a Simultaneous Perturbation Stochastic Approximation (SPSA) method and on an innovative inner algorithm, which allows it to quickly carry out the daily scheduling (charging/discharging) of the electrical energy storage systems. The proposed method is applied to a medium voltage (Institute of Electrical and Electronics Engineers) IEEE unbalanced test network, to demonstrate the effectiveness of the procedure in terms of computational effort while preserving the accuracy of the solution. The obtained results are also compared with the results of a Genetic Algorithm and of an exhaustive procedure