Questioning, exploring, narrating and playing in the control room to maintain system safety

Systems whose design is primarily aimed at ensuring efficient, effective and safe working, such as control rooms, have traditionally been evaluated in terms of criteria that correspond directly to those values: functional correctness, time to complete tasks, etc. This paper reports on a study of control room working that identified other factors that contributed directly to overall system safety. These factors included the ability of staff to manage uncertainty, to learn in an exploratory way, to reflect on their actions, and to engage in problem-solving that has many of the hallmarks of playing puzzles which, in turn, supports exploratory learning. These factors, while currently difficult to measure or explicitly design for, must be recognized and valued in design

Context-Awareness Enhances 5G Multi-Access Edge Computing Reliability

The fifth generation (5G) mobile telecommunication network is expected to support Multi- Access Edge Computing (MEC), which intends to distribute computation tasks and services from the central cloud to the edge clouds. Towards ultra-responsive, ultra-reliable and ultra-low-latency MEC services, the current mobile network security architecture should enable a more decentralized approach for authentication and authorization processes. This paper proposes a novel decentralized authentication architecture that supports flexible and low-cost local authentication with the awareness of context information of network elements such as user equipment and virtual network functions. Based on a Markov model for backhaul link quality, as well as a random walk mobility model with mixed mobility classes and traffic scenarios, numerical simulations have demonstrated that the proposed approach is able to achieve a flexible balance between the network operating cost and the MEC reliability.Comment: Accepted by IEEE Access on Feb. 02, 201

Designing and Operating Safe and Secure Transit Systems: Assessing Current Practices in the United States and Abroad, MTI Report 04-05

Public transit systems around the world have for decades served as a principal venue for terrorist acts. Today, transit security is widely viewed as an important public policy issue and is a high priority at most large transit systems and at smaller systems operating in large metropolitan areas. Research on transit security in the United States has mushroomed since 9/11; this study is part of that new wave of research. This study contributes to our understanding of transit security by (1) reviewing and synthesizing nearly all previously published research on transit terrorism; (2) conducting detailed case studies of transit systems in London, Madrid, New York, Paris, Tokyo, and Washington, D.C.; (3) interviewing federal officials here in the United States responsible for overseeing transit security and transit industry representatives both here and abroad to learn about efforts to coordinate and finance transit security planning; and (4) surveying 113 of the largest transit operators in the United States. Our major findings include: (1) the threat of transit terrorism is probably not universal—most major attacks in the developed world have been on the largest systems in the largest cities; (2) this asymmetry of risk does not square with fiscal politics that seek to spread security funding among many jurisdictions; (3) transit managers are struggling to balance the costs and (uncertain) benefits of increased security against the costs and (certain) benefits of attracting passengers; (4) coordination and cooperation between security and transit agencies is improving, but far from complete; (5) enlisting passengers in surveillance has benefits, but fearful passengers may stop using public transit; (6) the role of crime prevention through environmental design in security planning is waxing; and (7) given the uncertain effectiveness of antitransit terrorism efforts, the most tangible benefits of increased attention to and spending on transit security may be a reduction in transit-related person and property crimes

UAV-Empowered Disaster-Resilient Edge Architecture for Delay-Sensitive Communication

The fifth-generation (5G) communication systems will enable enhanced mobile broadband, ultra-reliable low latency, and massive connectivity services. The broadband and low-latency services are indispensable to public safety (PS) communication during natural or man-made disasters. Recently, the third generation partnership project long term evolution (3GPPLTE) has emerged as a promising candidate to enable broadband PS communications. In this article, first we present six major PS-LTE enabling services and the current status of PS-LTE in 3GPP releases. Then, we discuss the spectrum bands allocated for PS-LTE in major countries by international telecommunication union (ITU). Finally, we propose a disaster resilient three-layered architecture for PS-LTE (DR-PSLTE). This architecture consists of a software-defined network (SDN) layer to provide centralized control, an unmanned air vehicle (UAV) cloudlet layer to facilitate edge computing or to enable emergency communication link, and a radio access layer. The proposed architecture is flexible and combines the benefits of SDNs and edge computing to efficiently meet the delay requirements of various PS-LTE services. Numerical results verified that under the proposed DR-PSLTE architecture, delay is reduced by 20% as compared with the conventional centralized computing architecture.Comment: 9,

Towards the Internet of Smart Trains: A Review on Industrial IoT-Connected Railways

[Abstract] Nowadays, the railway industry is in a position where it is able to exploit the opportunities created by the IIoT (Industrial Internet of Things) and enabling communication technologies under the paradigm of Internet of Trains. This review details the evolution of communication technologies since the deployment of GSM-R, describing the main alternatives and how railway requirements, specifications and recommendations have evolved over time. The advantages of the latest generation of broadband communication systems (e.g., LTE, 5G, IEEE 802.11ad) and the emergence of Wireless Sensor Networks (WSNs) for the railway environment are also explained together with the strategic roadmap to ensure a smooth migration from GSM-R. Furthermore, this survey focuses on providing a holistic approach, identifying scenarios and architectures where railways could leverage better commercial IIoT capabilities. After reviewing the main industrial developments, short and medium-term IIoT-enabled services for smart railways are evaluated. Then, it is analyzed the latest research on predictive maintenance, smart infrastructure, advanced monitoring of assets, video surveillance systems, railway operations, Passenger and Freight Information Systems (PIS/FIS), train control systems, safety assurance, signaling systems, cyber security and energy efficiency. Overall, it can be stated that the aim of this article is to provide a detailed examination of the state-of-the-art of different technologies and services that will revolutionize the railway industry and will allow for confronting today challenges.Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED431C 2016-045Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED341D R2016/012Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; ED431G/01Agencia Estatal de Investigación (España); TEC2013-47141-C4-1-RAgencia Estatal de Investigación (España); TEC2015-69648-REDCAgencia Estatal de Investigación (España); TEC2016-75067-C4-1-

Local entanglements and utopian moves : an inquiry into train accidents

In 1996 after nearly fifty years in public ownership the British rail network was privatised. As a part of this what had been single organisation, British Rail, was broken into a set of different units which were individually sold off. Prominent among these were Railtrack plc (owner of the track, stations, signalling and other infrastructure), more than twenty train operating companies (TOCs) which received franchises to run trains (usually with government subsidies), and three companies which owned and leased rolling stock

Evaluation of a Set of TCP Features over Narrowband Radio Bearer for Train Communication

An engineering approach to the evaluation of the TCP as a narrowband bearer for short messages in the low latency train-trackside communication scenario is described in this report. The project was developed in cooperation with Bombardier Transportation Sweden AB as a part of the “ETCS over GPRS” venture. With the increase of the demands from the railway industry, the currently used circuit-switched GSM-R technology becomes unsatisfactory from the radio system capacity point of view and the need of a new solution is highly required. The packet-switched GPRS solution using TCP as a suite is under research for this specific scenario. The investigated problem in this report concerns the tuning of the retransmission mechanism, which includes the TCP features TCP_RTO_MIN and TCP_KEEPALIVE. This implies the tuning of those features to be able to detect a loss of communication and to react less aggressively for the short and instantaneous changes in the network delay. This thesis work began with a preparation phase in which a broad literature analysis of the background theory was made and followed by the development of applications that realizes the traffic model. Later in the performance phase the required changes were applied on the system and finally tested in a lab. The tests have been performed using one and four pairs of client-server applications communicating over an emulated link. The TCP features were modified at two levels, the TCP_RTO_MIN by a kernel recompilation and the TCP_KEEPALIVE by changes on the live system. Results from the tests have shown that for the higher than the default value of the TCP_RTO_MIN the less retransmissions were triggered. The TCP_KEEPALIVE has proven to be a sufficient feature to indicate a loss of the link. However the achieved improvement in performance was not as high as expected, but acceptable for this scenario. The train-trackside communication system could benefit from the proposed changes