Safety‐oriented discrete event model for airport A‐SMGCS reliability assessment

A detailed analysis of State of the Art Technologies and Procedures into Airport Advanced-Surface Movement Guidance and Control Systems has been provided in this thesis, together with the review ofStatistical Monte Carlo Analysis, Reliability Assessment and Petri Nets theories. This practical and theoretical background has lead the author to the conclusion that there is a lack of linkage in between these fields. At the same of time the rapid increasing of Air Traffic all over the world, has brought in evidence the urgent need of practical instruments able to identify and quantify the risks connected with Aircraft operations on the ground, since the Airport has shown to be the actual ‘bottle neck’ of the entire Air Transport System. Therefore, the only winning approach to such a critical matter has to be multi-disciplinary, sewing together apparently different subjects, coming from the most disparate areas of interest and trying to fulfil the gap. The result of this thesis work has come to a start towards the end, when a Timed Coloured Petri Net (TCPN) model of a ‘sample’ Airport A-SMGCS has been developed, that is capable of taking into account different orders of questions arisen during these recent years and tries to give them some good answers. The A-SMGCS Airport model is, in the end, a parametric tool relying on Discrete Event System theory, able to perform a Reliability Analysis of the system itself, that: • uses a Monte Carlo Analysis applied to a Timed Coloured Petri Net, whose purpose is to evaluate the Safety Level of Surface Movements along an Airport • lets the user to analyse the impact of Procedures and Reliability Indexes of Systems such as Surface Movement Radars, Automatic Dependent Surveillance-Broadcast, Airport Lighting Systems, Microwave Sensors, and so on… onto the Safety Level of Airport Aircraft Transport System • not only is a valid instrument in the Design Phase, but it is useful also into the Certifying Activities an in monitoring the Safety Level of the above mentioned System with respect to changes to Technologies and different Procedures.This TCPN model has been verified against qualitative engineering expectations by using simulation experiments and occupancy time schedules generated a priori. Simulation times are good, and since the model has been written into Simulink/Stateflow programming language, it can be compiled to run real-time in C language (Real-time workshop and Stateflow Coder), thus relying on portable code, able to run virtually on any platform, giving even better performances in terms of execution time. One of the most interesting applications of this work is the estimate, for an Airport, of the kind of A-SMGCS level of implementation needed (Technical/Economical convenience evaluation). As a matter of fact, starting from the Traffic Volume and choosing the kind of Ground Equipment to be installed, one can make predictions about the Safety Level of the System: if the value is compliant with the TLS required by ICAO, the A-SMGCS level of Implementation is sufficiently adequate. Nevertheless, even if the Level of Safety has been satisfied, some delays due to reduced or simplified performances (even if Safety is compliant) of some of the equipment (e.g. with reference to False Alarm Rates) can lead to previously unexpected economical consequences, thus requiring more accurate systems to be installed, in order to meet also Airport economical constraints. Work in progress includes the analysis of the effect of weather conditions and re-sequencing of a given schedule. The effect of re-sequencing a given schedule is not yet enough realistic since the model does not apply inter arrival and departure separations. However, the model might show some effect on different sequences based on runway occupancy times. A further developed model containing wake turbulence separation conditions would be more sensitive for this case. Hence, further work will be directed towards: • The development of On-Line Re-Scheduling based on the available actual runway/taxiway configuration and weather conditions. • The Engineering Safety Assessment of some small Italian Airport A-SMGCSs (Model validation with real data). • The application of Stochastic Differential Equations systems in order to evaluate the collision risk on the ground inside the Place alone on the Petri Net, in the event of a Short Term Conflict Alert (STCA), by adopting Reich Collision Risk Model. • Optimal Air Traffic Control Algorithms Synthesis (Adaptive look-ahead Optimization), by Dynamically Timed Coloured Petri Nets, together with the implementation of Error-Recovery Strategies and Diagnosis Functions

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Behavior analysis, from grinding or not of the teeth of piglets in nursery

The establishment of the social hierarchy of piglets after birth is one of the factors responsible for aggressive disputes among swine. This behavior results in lesions on the face of piglets and on the nipple of sows. Methods such as clipping or grinding of teeth procedures are conducted to the reduction of losses related to the welfare and growth performance of the animals. However, this management has been questioned about the pain and stress. Since 2001, The European Union legislation which describes patterns of animal welfare prohibits the handling of clipping or grinding of teeth of piglets as a routine measure. The objective of this study was to evaluate the effect of grinding or not of teeth in piglet behavior in the nursery. Were used to obtain the data: 34 sows and their piglets, with 11.3 on average. The study was conducted during the summer, in the city of Concordia, SC. At birth, the piglets were separated into rooms according to the order of birth and type of treatment directed to the litters. The management of tooth grind was always held on the second day postpartum along with weighing, the tail docking and castration of male piglets. The behavior was obtained with the aid of an ethogram with variables like sleeping, breastfeeding, eating and drinking water, stereotypies, aggression, standing, lying or sitting, playfulness and exploratory behavior. The observations were made during the twenty one and twenty eight days, until weaning. Data were collected in periods of three days during each week, six hours a day and every five minutes. The data were analyzed on a complete randomized block design with repeated measures. We used a mixed model with fixed effects of treatment, shift, week, and their interactions block using the MIXED procedure (SAS Inst. Inc., Cary, NC). The behavior studied is the percentage of animals in the activity when evaluated. The comparison of the mean was performed by Fisher's least significant difference. Analyzing the behavior of piglets from varying treatments, shift and week, we found an important effect in all proposals. After confronting variables such as treatment and day shift, only the behavior of eating and sitting had no significant effect. But when contrasted treatment and week, important behaviors such as exploratory and playfulness didn't show significant effect. When evaluating individual behavior the playfulness showed significant effect when related to different kinds of handling of teeth. The standing and playful behavior, important evidence of comfort and stress of animals, were the ones which had no significant effect when the variables treatment x week x shift were opposed. The stereotyped behavior, important for the welfare of confined animals, showed no significant effect only for opposing variables: week x shift and treatment, indicating a high correlation between treatment, time of confinement and lack of entertainment of confined animals. Significant effect was found for agonistic behavior in all opposing variables, indicating normal behavior of piglets, both in the early days of birth and the following weeks, due to increased body and consequent reduction in the physical space of the stall. It is concluded from the treatments that the grinding of piglets teeth in the nursery is effective for reducing aggressive behavior and there were fewer animals with injuries in pig farms

Análise do comportamento, a partir do desgaste ou não dos dentes de leitões, na maternidade

O artigo não apresenta resumo em português