scholarly journals A Dynamic Linear Hashing Method for Redundancy Management in Train Ethernet Consist Network

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Xiaobo Nie ◽  
Lide Wang ◽  
Baohua Wang ◽  
Biao Liu ◽  
Ping Shen

Massive transportation systems like trains are considered critical systems because they use the communication network to control essential subsystems on board. Critical system requires zero recovery time when a failure occurs in a communication network. The newly published IEC62439-3 defines the high-availability seamless redundancy protocol, which fulfills this requirement and ensures no frame loss in the presence of an error. This paper adopts these for train Ethernet consist network. The challenge is management of the circulating frames, capable of dealing with real-time processing requirements, fast switching times, high throughout, and deterministic behavior. The main contribution of this paper is the in-depth analysis it makes of network parameters imposed by the application of the protocols to train control and monitoring system (TCMS) and the redundant circulating frames discarding method based on a dynamic linear hashing, using the fastest method in order to resolve all the issues that are dealt with.

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3107 ◽  
Author(s):  
Ramon Sanchez-Iborra ◽  
José Santa ◽  
Jorge Gallego-Madrid ◽  
Stefan Covaci ◽  
Antonio Skarmeta

Internet of Vehicles (IoV) is a hot research niche exploiting the synergy between Cooperative Intelligent Transportation Systems (C-ITS) and the Internet of Things (IoT), which can greatly benefit of the upcoming development of 5G technologies. The variety of end-devices, applications, and Radio Access Technologies (RATs) in IoV calls for new networking schemes that assure the Quality of Service (QoS) demanded by the users. To this end, network slicing techniques enable traffic differentiation with the aim of ensuring flow isolation, resource assignment, and network scalability. This work fills the gap of 5G network slicing for IoV and validates it in a realistic vehicular scenario. It offers an accurate bandwidth control with a full flow-isolation, which is essential for vehicular critical systems. The development is based on a distributed Multi-Access Edge Computing (MEC) architecture, which provides flexibility for the dynamic placement of the Virtualized Network Functions (VNFs) in charge of managing network traffic. The solution is able to integrate heterogeneous radio technologies such as cellular networks and specific IoT communications with potential in the vehicular sector, creating isolated network slices without risking the Core Network (CN) scalability. The validation results demonstrate the framework capabilities of short and predictable slice-creation time, performance/QoS assurance and service scalability of up to one million connected devices.


Author(s):  
Zoleikha Abdollahi Biron ◽  
Satadru Dey ◽  
Pierluigi Pisu

Connected vehicles are one of the promising technologies for future Intelligent Transportation Systems (ITS). Despite being the potentially beneficial in creating an efficient, sustainable and green transportation system, connected vehicles presents a set of specific challenges from safety and reliability standpoint. The first challenge arises from the information lost due to unreliable communication network which affects the control/management system of the individual vehicles and the overall system. Secondly, faulty sensors can affect the individual vehicle’s safe operation and in turn will create a potentially unsafe node in the vehicular network. Therefore, it is of utmost importance to take these issues into consideration while designing the control/management algorithms of the individual vehicles as a part of connected vehicle system. In this paper, we consider a connected vehicle system under Co-operative Adaptive Cruise Control (CACC) and propose a diagnostic scheme that deals with these aforementioned challenges. The effectiveness of the overall diagnostic scheme is verified via simulation studies.


Author(s):  
Abdulaziz Ahmed Thawaba ◽  
Azizul Azhar Ramli ◽  
Mohd. Farhan Md. Fudzee ◽  
Junzo Wadata ◽  
◽  
...  

Safety-critical systems (SCS) are the most significant systems that affect our daily life in many areas such as flight control systems, railway systems, medical devices, nuclear systems, and military weapons. SCS failures could result in losing life or serious injuries. Improving the practices during development phases of SCS can reduce failures up to 40%, thus resulting developers to follows specific development practices and techniques. Developers should improve safety-critical system development (SCSD) by taking into account all factors and understanding the causes of failure. Previous studies have highlighted the causes of failure during the development of SCS, but for specific areas such as designs, requirements, or the human factor, while developers need to know the causes of failure in all areas and the relationship between them clearly and comprehensively. This research aims to analyze SCSD characteristics and discuss performance improvement as well as causes of failure. This paper proposed a guideline that helps developers reduce the causes of failure during SCS development. This guide has four characteristics, each with a role in improving SCSD and reducing causes of failure.


Author(s):  
Arash Aziminejad ◽  
Andrew W. Lee

Ethernet was commercially introduced in 1980 and standardized in 1985 as IEEE 802.3. Due to the instability and unreliability of the initial introduction, safety critical systems have been slow to adapt Ethernet technologies. It is only until the Information Age brought on by the globalization of Internet in the 1990s that network gears become more cost effective, reliable, and technically suitable. With many Ethernet technologies to pick from, selection of a suitable network topology can be challenging. This paper offers insight on the problem of the optimum choice of an Ethernet technology for the purpose of safety critical system. Example of a typical CBTC system will be given along with the key design parameters and several Ethernet technologies analyzed. Simulation models are built on the basis of the two most common Ethernet technologies to provide means of comparison, and numerical results are presented in the paper.


2021 ◽  
Author(s):  
Anna Arestova ◽  
Wojciech Baron

The rapid development in information and communication technology confronts designers of real-time systems with new challenges that have arisen due to the increasing amount of data and an intensified interconnection of functions. This is e.g. driven by recent trends such as automated driving in the automotive field and digitization in factory automation. For distributed safety-critical systems, this progression has the impact that the complexity of scheduling tasks with precedence constraints organized in so-called task chains increases the more data has to be exchanged between tasks and the more functions are involved. Especially when data has to be transmitted over an Ethernet-based communication network, the coordination between the processing tasks running on different end-devices and the communication network has to be ensured to meet strict end-to-end deadlines of task chains. In this work, we present a heuristic approach that computes schedules for distributed and data-dependent task chains consisting of preemptive and periodic tasks, taking into account the network communication delays of time-sensitive networks. Our algorithm is able to solve large problems for synthetic network topologies with randomized data dependencies in a few seconds. A high success rate was achieved, which can also be further enhanced by relaxing the deadline conditions.


Author(s):  
Abdessamad Jarrar ◽  
Youssef Balouki

Antilock Braking System (ABS) is one of the most critical systems in the context of vehicles' mechatronics. The main purpose of the ABS system is allowing the wheels to stop while preventing sliding. It is responsible for ensuring a secure stopping of the vehicle, a very critical factor in trip safety. Therefore, the process of its construction should be performed with high care, and this is why theoretical modeling is highly needed. In order to help engineers to develop and study such a critical system, we propose a standard model that includes the essence of Antilock Braking System using a formal method called Event-B. This model may be used to reveal some bugs during proving that may go otherwise undetected. At the same time, the model can be animated to observe the system behavior.


2020 ◽  
Vol 27 (9) ◽  
pp. 2501-2522 ◽  
Author(s):  
Pei-Yuan Hsu ◽  
Marco Aurisicchio ◽  
Panagiotis Angeloudis ◽  
Jennifer Whyte

PurposeDelays in construction projects are both disruptive and expensive. Thus, potential causes of schedule deviation need to be identified and mitigated. In previous research, delay factors were predominantly identified through surveys administered to stakeholders in construction projects. Such delay factors are typically considered individually and presented at the same level without explicitly examining their sequence of occurrence and inter-relationships. In reality, owing to the complex structure of construction projects and long execution time, non-conformance to schedule occurs by a chain of cascading events. An understanding of these linkages is important not only for minimising the delays but also for revealing the liability of stakeholders. To explicitly illustrate the cause–effect and logical relationship between delay factors and further identify the primary factors which possess the highest significance toward the overall project schedule delay, the fault tree analysis (FTA) method, a widely implemented approach to root cause problems in safety-critical systems, has been systematically and rigorously executed.Design/methodology/approachUsing a case study, the in-depth analysis for identifying the most fundamental delay factors has been fulfilled through FTA's tree structure. The logical deduction for mapping and visualising the chronological and cause–effect relationships between various delay factors has been conducted through the logical gate functions of FTA based on the data collected from the site event log, pre-fabricated structural component manufacturing log and face-to-face interview with project stakeholders.FindingsThe analysis identified multiple delay factors and showed how they are linked logically and chronologically from the primary causes to the ultimate undesired event in a rigorous manner. A comparison was performed between the proposed FTA model and the conventional investigation method for revealing the responsibility employed in the construction industry, consisting of event logs and problem reports. The results indicate that the FTA model provides richer information and a clearer picture of the network of delay factors. Importantly, the ability of FTA in revealing the causal connection between the events leading to the undesired delays and in comprehending their prominence in the real-world construction project has been clearly displayed.Originality/ valueThis study demonstrates a new application of FTA in the construction sector allowing the delay factors to be understood and visualised from a new perspective. The new approach has practical use in finding and removing root causes of the delay, as well as clarifying the attribution of responsibility that causes the delay.


2012 ◽  
Vol 2 (2) ◽  
pp. 68-90 ◽  
Author(s):  
PhaniKumar Singamsetty ◽  
SeethaRamaiah Panchumarthy

The main objective of this research paper is designing automatic fuzzy parameter selection based dynamic fuzzy voter for safety critical systems with limited system knowledge. Existing fuzzy voters for controlling safety critical systems and sensor fusion are surveyed and safety performance is empirically evaluated. The major limitation identified in the existing fuzzy voters is the static fuzzy parameter selection. Optimally selected static fuzzy parameters work only for a particular set of data with the known data ranges. In this paper, a dynamic or automatic fuzzy parameter selection method for fuzzy voters is proposed based on the statistical parameters of the local set of data in each voting cycle. Safety performance is empirically evaluated by running the static and dynamic fuzzy voters on a simulated triple modular redundant (TMR) system for 10000 voting cycles. Experimental results show that proposed Dynamic fuzzy voter is giving almost 100% safety if two of the three modules of the TMR System are error free. Dynamic voter is designed in such a way that it can be plugged in and used in any safety critical system without having any knowledge regarding the data produced and their ranges.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Zong-Yuan Li ◽  
Guang-Jun Jiang ◽  
Hong-Xia Chen ◽  
Hai-Bin Li ◽  
Hong-Hua Sun

The reliability assessment of special vehicles has become very important. However, due to the special structure of special vehicles, it is difficult to collect a large amount of experimental data. The use of traditional fault tree analysis cannot accurately assess product reliability. In this paper, dynamic fault trees are used to model the critical systems of special vehicles, and discrete Bayesian networks are used to evaluate the reliability of critical systems of special vehicles, which solved the problems of difficulty in accurately describing complex systems in the process of system reliability analysis and difficulty in obtaining accurate data in the process of analysis. Finally, through the combination of expert experience and the evaluation of the calculation results, the rationality of the method used in this paper in the reliability evaluation of special vehicles is verified.


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