scholarly journals A hierarchical distributed protocol for MPLS path creation

Author(s):  
M. El-Darieby ◽  
D. Petriu ◽  
J. Rolia
Author(s):  
Paulius Stankaitis ◽  
Alexei Iliasov ◽  
Tsutomu Kobayashi ◽  
Yamine Aït-Ameur ◽  
Fuyuki Ishikawa ◽  
...  

AbstractThe decentralised railway signalling systems have a potential to increase capacity, availability and reduce maintenance costs of railway networks. However, given the safety-critical nature of railway signalling and the complexity of novel distributed signalling solutions, their safety should be guaranteed by using thorough system validation methods. To achieve such a high-level of safety assurance of these complex signalling systems, scenario-based testing methods are far from being sufficient despite that they are still widely used in the industry. Formal verification is an alternative approach which provides a rigorous approach to verifying complex systems and has been successfully used in the railway domain. Despite the successes, little work has been done in applying formal methods for distributed railway systems. In our research we are working towards a multifaceted formal development methodology of complex railway signalling systems. The methodology is based on the Event-B modelling language which provides an expressive modelling language, a stepwise development and a proof-based model verification. In this paper, we present the application of the methodology for the development and verification of a distributed protocol for reservation of railway sections. The main challenge of this work is developing a distributed protocol which ensures safety and liveness of the distributed railway system when message delays are allowed in the model.


2018 ◽  
Vol 10 (4) ◽  
pp. 5-38
Author(s):  
Sylwia Przytuła

Abstract Objective: The theoretical purpose of this article is to present social, technological, economic and cultural trends that determine the global labor market, new needs on the labor market and create new competences and professions. The goal of empirical research was to diagnose the most challenging trends for HR specialists and to identify key competencies on the global workforce market. Methodology: The paper, apart from desk-research and literature review, presents the results of exploratory pilot research. Purposive sampling was applied and the questionnaire was addressed to 44 managers and HR specialists (“key informants”, Myers, 2009) who are participants of postgraduate studies in HR Business Partner, Human Resource Management. The conducted research was idiographic, which means that its conclusions concern only the studied population. But resignation from a broad generalization of results does not necessarily reduce their cognitive value (Chełpa, 2003). Findings: The biggest challenges for HR were: retention of employees and building their loyalty, shortage of employees on the labor market, management of employees of different generations. It can be said that these challenges are inherent with global trends and problems faced by employers. Respondents pointed to the most desirable competences nowadays and in the near future: IT competencies, intercultural skills, creative and cognitive thinking, ability to work in virtual and multicultural teams. To the key personnel activities which in the next 5 years will gain in importance belonged: mobile working, hiring experts (freelancers), crowd working, portfolio work. Value Added: This theoretical-empirical study organizes the current results of foresight research on HR trends, in order to develop an aggregated list of the most desirable competencies on the global labor market. Knowledge about the missing, niche competencies of employees pointed out by employers will allow targeting education systems and equipping employees equipped with the most demanded skills and knowledge. Recommendations: The challenges of the global labor market presented in this article will contribute to disappearance of many previous professions, changes in the nature of work and the emergence of its new forms. In the coming years, many HRM practices will require the revision and implementation of new personnel solutions for recruitment, motivation and career path creation. A flexible career understood as a “portfolio of projects and experiences” of an employee will develop in any direction. Communication model in companies will also be transformed, as mobile devices will become an office, a training room and a personal assistant.


2016 ◽  
Vol 27 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Evaldo Rodrigues ◽  
Gustavo De-Deus ◽  
Erick Souza ◽  
Emmanuel João Nogueira Leal Silva

Abstract The aim of the present study was to prospectively assess the frequency of teeth in which the Reciproc instruments were able to reach the full working length (WL). This case series study enrolled 277 consecutive teeth requiring primary endodontic treatment performed with the Reciproc system (VDW) without a previous glide path by 3 experienced endodontists. Instruments R25, R40 or R50 were selected, respectively, for narrow, medium and large canals, according to the preoperative radiographs, as per manufacturer recommendation. Canals were instrumented and classified as reaching the full WL (RFWL) and not reaching the full WL (NRFWL), according to the ability of the Reciproc instrument to reach without a glide path the full electronically determined WL. Finally, canals were filled using a single matched cone technique. Pearson's squared-chi test compared the frequency distributions of canals classified as RFWL and NRFWL. From a total pool of 673 root canals, Reciproc instruments reached the FWL in 96.28% of cases and 3 fractures occurred. For narrow canals the percentage of RFWL was 95.37% with 3 fractures. For medium and large canals, the R40 or R50 instruments reached the FWL in 98.51% and 97.62% of the cases respectively, with no fracture. Enlarging of root canals using the Reciproc instruments up to the FWL without a glide path is successful in a great percentage of cases. This case series suggests the possibility of using a single instrument to enlarge the root canal space of teeth by a simpler approach without an a prioriglide path procedure.


2017 ◽  
Vol 70 ◽  
pp. 551-562 ◽  
Author(s):  
Teis Hansen ◽  
Antje Klitkou ◽  
Mads Borup ◽  
Lisa Scordato ◽  
Nina Wessberg

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