An HCPN Pattern for Railway Safety Critical Scenarios Formal Modeling

Author(s):  
Zakaryae Boudi ◽  
El Miloudi El Koursi ◽  
Simon Collart-Dutilleul

Analyzing railway critical scenarios usually involves a large team of diverse railway abilities and skills. This paper presents a formal modeling pattern for Hierarchical Colored Petri Nets (HCPN) in modeling railway safety critical scenarios. Indeed, under the French project called “PERFECT”, our long-term objective is to formalize and automate a significant part of railway scenarios modeling. The purpose of this contribution is to bring a first proposition of a standardized modeling way able to deal with the models complexity resulting from the various modeling capabilities for railway scenarios. In fact, HCPN modeling freedom is preventing from accurate information aggregation and a beneficial use of those models in an overall safety analysis. The proposed pattern is based on modular High Level Petri Nets and consists in describing all the railway scenario episodes while incorporating most relevant safety components of the system, such as safety regulation procedures, interlocking and even human involvement, enabling a larger gathering of information and allowing the study of diverse issues in a same global model. This work intends to bring a concrete and reusable HCPN pattern for modeling in order to facilitate studies of accidental scenarios considering automatic mechanisms and human tasks. A concrete application of the pattern was made for the real accidental scenario of “Saint Romain en Gier”.

2016 ◽  
Vol 15 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Eric R. Fenstad ◽  
Sara E. Wordingham ◽  
Keith M. Swetz

Summary: Pulmonary hypertension (PH) can be associated with a high level of symptom burden from the disease as well as its treatment. Involvement of palliative care (PC) services may help facilitate discussion regarding goals of care, prognostic planning, and treatment options focused on improving quality of life (QOL). Background: PC is active total care of a patient whose disease is not fully responsive to curative therapies, with symptom control as the top priority. After a life-limiting diagnosis is made, health care teams and patients determine prognosis, whether cure is attainable or reasonable, what treatment options are available, risks and benefits of associated treatments, and how treatment or nontreatment will impact QOL and survival. QOL is often the focus of palliative interventions, with the goal to minimize symptoms and empower patients with accurate information to help affirm life and meet objectives of care. Implications for clinicians: PC can begin at the onset of symptoms in a disease that cannot be cured. Early PC may help facilitate discussion regarding goals of care when patient expectations are discordant with prognosis. While PC is a responsibility of all clinicians, subspecialist assistance can be helpful when a clinical decline occurs, in the setting of uncertainty, when patients are removed from the transplant list, or when long-term QOL issues are present. Conclusion: Communication with patients who have PH can be delicate and requires an understanding of the disease's process, trajectory, and prognosis. PC teams possess communication skills that may benefit patients and providers with QOL optimization, delivery of difficult news, advanced care planning, and shared decision-making.


2016 ◽  
Vol 26 (3) ◽  
pp. 339-365 ◽  
Author(s):  
Marcin Szpyrka ◽  
Jerzy Biernacki ◽  
Agnieszka Biernacka

Abstract RTCP-nets are high level Petri nets similar to timed colored Petri nets, but with different time model and some structural restrictions. The paper deals with practical aspects of using RTCP-nets for modeling and verification of real-time systems. It contains a survey of software tools developed to support RTCP-nets. Verification of RTCP-nets is based on coverability graphs which represent the set of reachable states in the form of directed graph. Two approaches to verification of RTCP-nets are considered in the paper. The former one is oriented towards states and is based on translation of a coverability graph into nuXmv (NuSMV) finite state model. The later approach is oriented towards transitions and uses the CADP toolkit to check whether requirements given as μ-calculus formulae hold for a given coverability graph. All presented concepts are discussed using illustrative examples


Author(s):  
G. R. Petrosyan ◽  
L. A. Ter-Vardanyan ◽  
A. V. Gaboutchian

In this paper we present a model of biometric identification system transformed into Petri Nets. Petri Nets, as a graphical and mathematical tool, provide a uniform environment for modelling, formal analysis, and design of discrete event systems. The main objective of this paper is to introduce the fundamental concepts of Petri Nets to the researchers and practitioners, both from identification systems, who are involved in the work in the areas of modelling and analysis of biometric identification types of systems, as well as those who may potentially be involved in these areas. In addition, the paper introduces high-level Petri Nets, as Colored Petri Nets (CPN). In this paper the model of Colored Petri Net describes the identification process much simpler.


2006 ◽  
Vol 27 (4) ◽  
pp. 218-228 ◽  
Author(s):  
Paul Rodway ◽  
Karen Gillies ◽  
Astrid Schepman

This study examined whether individual differences in the vividness of visual imagery influenced performance on a novel long-term change detection task. Participants were presented with a sequence of pictures, with each picture and its title displayed for 17  s, and then presented with changed or unchanged versions of those pictures and asked to detect whether the picture had been changed. Cuing the retrieval of the picture's image, by presenting the picture's title before the arrival of the changed picture, facilitated change detection accuracy. This suggests that the retrieval of the picture's representation immunizes it against overwriting by the arrival of the changed picture. The high and low vividness participants did not differ in overall levels of change detection accuracy. However, in replication of Gur and Hilgard (1975) , high vividness participants were significantly more accurate at detecting salient changes to pictures compared to low vividness participants. The results suggest that vivid images are not characterised by a high level of detail and that vivid imagery enhances memory for the salient aspects of a scene but not all of the details of a scene. Possible causes of this difference, and how they may lead to an understanding of individual differences in change detection, are considered.


2015 ◽  
Vol 12 (1) ◽  
pp. 1-12
Author(s):  
Sarah Hackett

Drawing upon a collection of oral history interviews, this paper offers an insight into entrepreneurial and residential patterns and behaviour amongst Turkish Muslims in the German city of Bremen. The academic literature has traditionally argued that Turkish migrants in Germany have been pushed into self-employment, low-quality housing and segregated neighbourhoods as a result of discrimination, and poor employment and housing opportunities. Yet the interviews reveal the extent to which Bremen’s Turkish Muslims’ performances and experiences have overwhelmingly been the consequences of personal choices and ambitions. For many of the city’s Turkish Muslim entrepreneurs, self-employment had been a long-term objective, and they have succeeded in establishing and running their businesses in the manner they choose with regards to location and clientele, for example. Similarly, interviewees stressed the way in which they were able to shape their housing experiences by opting which districts of the city to live in and by purchasing property. On the whole, they perceive their entrepreneurial and residential practices as both consequences and mediums of success, integration and a loyalty to the city of Bremen. The findings are contextualised within the wider debate regarding the long-term legacy of Germany’s post-war guest-worker system and its position as a “country of immigration”.


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