Fault-Tolerance by Resilient State Transition for Collaborative Cyber-Physical Systems

Collaborative Cyber-Physical Systems (CCPS) are systems where several individual cyber-physical systems collaborate to perform a single task. The safety of a single Cyber-Physical System (CPS) can be achieved by applying a safety mechanism and following standard processes defined in ISO 26262 and IEC 61508. However, due to heterogeneity, complexity, variability, independence, self-adaptation, and dynamic nature, functional operations for CCPS can threaten system safety. In contrast to fail-safe systems, where, for instance, the system leads to a safe state when an actuator shuts down due to a fault, the system has to be fail-operational in autonomous driving cases, i.e., a shutdown of a platooning member vehicle during operation on the road is unacceptable. Instead, the vehicle should continue its operation with degraded performance until a safe state is reached or returned to its original state in case of temporal faults. Thus, this paper proposes an approach that considers the resilient behavior of collaborative systems to achieve the fail-operational goal in autonomous platooning systems. First, we extended the state transition diagram and introduced additional elements such as failures, mitigation strategies, and safe exit to achieve resilience in autonomous platooning systems. The extended state transition diagram is called the Resilient State Transition Diagram (R-STD). Second, an autonomous platooning system’s perception, communication, and ego-motion failures are modeled using the proposed R-STD to check its effectiveness. Third, VENTOS simulator is used to verify the resulting resilient transitions of R-STD in a simulation environment. Results show that a resilient state transition approach achieves the fail-operational goal in the autonomous platooning system.

Examining sub-daily tornado warning performance and associated environmental characteristics

Increasing tornado warning skill in terms of the probability of detection and false alarm ratio remains an important operational goal. Although many studies have examined tornado warning performance in a broad sense, less focus has been placed on warning performance within sub-daily convective events. In this study, we use the NWS tornado verification database to examine tornado warning performance by order-of-tornado within each convective day. We combine this database with tornado reports to relate warning performance to environmental characteristics. On convective days with multiple tornadoes, the first tornado is warned significantly less often than the middle and last tornadoes. More favorable kinematic environmental characteristics, like increasing 0–1-km shear and storm-relative helicity, are associated with better warning performance related to the first tornado of the convective day. Thermodynamic and composite parameters are less correlated to warning performance. During tornadic events, over half of false alarms occur after the last tornado of the day decays, and false alarms are twice as likely to be issued during this time than before the first tornado forms. These results indicate that forecasters may be better “primed” (or more prepared) to issue warnings on middle and last tornadoes of the day, and must overcome a higher threshold to warn on the first tornado of the day. To overcome this challenge, using kinematic environmental characteristics and intermediate products on the watch-to-warning scale may help.

Production, Measurement and Applications of Vacuum Systems

The most common type of vacuum pumps and measuring gauges based on available literature are studied with emphasis on how new research and development will enable the new generation of vacuum technology specially in designing, its operational procedure and applications. The technologies were developed to meet the operational goal which include vacuum chamber structures, compatible materials, specialized vacuum pump and gauges. There are many areas where different vacuum condition is required for conducting experiments therefore modeling of pumping system is on demand. The basic understanding of how and when the particular pumping and measurement system can be applied most effectively and economically is essential. The poor choice of pumping and measurement system will interfere the scientific objectives and may leads to substantial maintenance demands and an unpleasant working environment. The development and fundamental investigation of innovative vacuum techniques for creation and measurement of vacuum used for various applications necessary for the research work to be done in future are presented.

The SafeBirth Clinic

The effective utilization of capacity is an important operational goal that managers strive to achieve. Most textbooks use the following simple “bottleneck formula” to illustrate the calculation of process capacity: the capacity of each resource is first calculated by examining that resource in isolation; process capacity is then taken as the smallest (bottleneck) among the resource capacities. The bottleneck formula is, in fact, an approximation of the true process capacity and correctly calculates capacity only in some straightforward settings, for example, in processes where each activity requires only one resource and in processes where each resource is dedicated to only one activity. However, when activities require multiple resources simultaneously (collaboration) and when resources are capable of doing multiple activities (multitasking), the simple formula can be significantly inaccurate. Further, several commonly held managerial insights related to process capacity and least-capacity resources that emerge from the formula can be misleading. The main goal of this case is to alert students that, for processes with collaboration and multitasking, the use of the bottleneck formula brings the potential danger of reaching incorrect conclusions about capacity and what constitutes a bottleneck of a process and may eventually lead to erroneous decisions with significant financial impact, for example, investing in procuring an expensive resource without being able to realize the presumed increase in capacity. More generally, the case illustrates the principles of process capacity and bottleneck structures and clarifies some often-repeated misunderstandings on the relationship between process capacity and least-capacity resources. The case also illustrates the importance of using Gantt charts for conveniently displaying schedules of activities.

A Functional Driver Analyzing Concept

It is evident that a lot of accidents occur because of drowsiness or inattentiveness of the driver. The logical consequence is that we have to find methods to better analyze the driver. A lot of research has been spent on camera-based systems which focus on the driver's eye gaze or his head movement. But there are few systems that provide camera-free driver analyzing. This is the main goal of the work presented here which is structured in three phases, with the operational goal of having a working driver analyzer implemented in a car. The main question is: is it possible to make statements concerning the driver and his state by using vehicle data from the CAN Bus only? This paper describes the current state of driver analyzing, our overall system architecture, as well as future work. At the moment, we focus on detecting the driving style of a person.