Experimental Performance Assessment of an Automated Shuttle in a Complex, Public Road Environment

Due to the huge number of diverse wireless devices and technologies, spectacular increases in the number of wireless subscribers, advent of new applications and continuous demand for higher data-rates, the radio frequency (RF) spectrum is becoming more and more crowded. This development calls for systems and devices that are aware of their surrounding RF environment, so they can facilitate flexible, efficient, and reliable operation and utilization of the available spectral resources. Thus, the spectrum sensing is becoming progressively more important to recent and future wireless communication systems for identifying underutilized spectrum and characterizing interference, with the goal of achieving reliable and efficient operation. Cognitive radio is an intelligent radio that is aware of its surrounding environment, capable of learning and adapting its behavior and operation to provide a good match to its surrounding environment and to the user’s needs. Spectrum sensing is the key requirement and one of the most challenging issues for the cognitive radio system. This chapter presents a comprehensive survey of the physical layer spectrum sensing techniques for cognitive radios. The major challenges in spectrum sensing are outlined and several techniques for improving spectrum sensing performance are discussed. Further, a hybrid model for non-cooperative spectrum sensing is presented; with this terminology, the proper channelization of the three techniques is introduced, with relevant discussion. This approach helps in detecting the idle spectrum opportunistically, with better spectrum utilization under non-cooperative sensing, resulting in enhanced spectrum efficiency. We also explore sensing under a cooperative environment. The approach presented aids in opportunistically detecting idle spectrum bands (spectrum holes that are the underutilized sub-bands of the radio spectrum), with better utilization of the spectrum than under non-cooperative sensing, and increased overall spectrum efficiency.

The offshore energy industry relies on heavy-duty equipment to execute complex operations in harsh environments over a long time with remote control and limited maintenance. But how is this equipment powered and controlled to enable reliable and safe operation? Hydraulics have been often used because of the high robustness and safety; but hydraulics also include complex installation, low energy-efficiency and potential environmental risks. On the flipside, subsea electrification seems cost-intensive due to its high power and large batteries needed. This paper explains how a novel subsea electric actuator technology enables a sustainable energy transition combining the ability to move high forces while being cost effective. For CO2 storage, it enables an all-electric subsea tree, comparable in price to a traditional hydraulic tree, but without demanding expensive umbilicals or topside hydraulic power units. In applications requiring long control distances, such as oil & gas fields with long subsea tiebacks or deepsea mining, it allows safe and reliable operation with minimal electric power consumption, capable of precisely handling even high loads.

Preloaded bolted connections are one of the most used approaches for anchoring steel structures and equipment. Preload is induced by a mechanical tightening of the nut with the required torque. In the case of anchor bolts embedded in a concrete base, the prescribed tightening procedure has to be followed for safe and reliable operation. The present paper addresses the problem of anchoring a new casting pedestal using the original anchor bolts. The aim was to verify the original anchoring system’s reliable and safe operation, taking into account the current condition of the bolts. The analysed anchoring bolts are subjected to cyclic (disappearing) stress during the rotation of the casting pedestal. If the interplays between the anchor bolt and the concrete foundation were damaged, production would shut down, resulting in high economic losses. For this reason, the authors used a modified nut with a lightened first thread when investigating the actual state of the anchoring and setting the required preload. The shape and dimensions of the nut were determined based on the results of numerical modelling. The experimental measurements consisted of two phases. In the first phase, the values of axial forces in the anchor bolts at the required preload were set using the designed dynamometers. The second phase was focused on the operational measurements. The methodology of measuring the axial forces and the interpretation of the results obtained, including a comprehensive view of the anchoring safety, provides relevant evidence of the functionality and effectiveness of the proposed solution. Based on the results of the operational measurement and the prescribed handling of the casting pedestal, the lifespan of the anchoring was determined to be 3650 days under the loading cycles to date.

Using hydrogen fuel cells for power systems, temperature conditions are important for efficient and reliable operations, especially in low-temperature environments. A heating system with an electrical energy buffer is therefore required for reliable operation. There is a research gap in finding an appropriate control strategy regarding energy efficiency and reliable operations for different environmental conditions. This paper investigates heating strategies for the subfreezing start of a fuel cell for portable applications at an early development stage to enable frontloading in product engineering. The strategies were investigated by simulation and experiment. A prototype for such a system was built and tested for subfreezing start-ups and non-subfreezing start-ups. This was done by heating the fuel cell system with different control strategies to test their efficiency. It was found that operating strategies to heat up the fuel cell system can ensure a more reliable and energy-efficient operation. The heating strategy needs to be adjusted according to the ambient conditions, as this influences the required heating energy, efficiency, and reliable operation of the system. A differentiation in the control strategy between subfreezing and non-subfreezing temperatures is recommended due to reliability reasons.

Induction heating (IH) technology is widely recognized and utilized in residential applications due to its high efficiency and safe operating characteristics. Resonant inverter circuits are widely used in IH systems because of their high efficiency and ability to perform soft switching. Among the various resonant inverters used in IH systems, the single-switch quasi-resonant (SSQR) inverter topology is typically preferred for low-cost and low-output-power applications. Despite its cost advantage, the SSQR topology has a relatively narrow soft-switching range, which can be unstable depending on the electrical parameters of the load and the resonant converter circuit. Accurately determining the capacitance value of the resonant capacitor and the inductance value of the induction coil, which are the key circuit elements of the SSQR induction cooker, is crucial for designing a reliable, efficient, and durable cooking system. In other words, there exists a critical relationship between the resonant converter circuit parameters, load characteristics, and safe operating conditions. Additionally, when considering closed-loop control methods used for power control and safety, selecting appropriate resonant circuit elements becomes vital in ensuring both reliable and efficient operation. This paper focuses on a novel and simplified design method for the SSQR inverter utilized in household appliances. The proposed method and its advantages in terms of the safe operating area of the switch are theoretically investigated and verified through simulations and prototype circuits.

The three phase induction motor is a popularly used machine in many of the industries, which is well known for its robustness, reliability, cost effectiveness, efficient and safe operation. The unnoticed manufacturing failure, mistakes during repair work, exceeding life time may be some of the causes of the induction motor failure, which may lead to the unknown shut down time of the industry. The condition monitoring plays important role as it has the influence on the production of materials and profit. In our work, the induction motor is modelled using stationary reference frame and analysed for single phasing stator fault. The techniques used in detecting the single phasing (open circuit) failures are Park’s vector approach and Fast Fourier Transform (FFT). Park’s vector approach is used for detecting the faults occurring at various phases and FFT is used for detecting the faults of the induction motor working under no load and varying loading conditions.

Programmable Logic Controllers (PLCs) are gaining traction in microgrid operation due to their real-time deployment, reliable and robust operation, and fast response, even in harsh environments. Recognizing the critical need for robust and reconfigurable microgrid control and operation, this research proposes a hardware test-bench prototype using the Reconfigurable Allen-Bradley—Micro820/2080-LC20-20QBB PLC to demonstrate control algorithms aiming for efficient control, energy management, and resilient microgrid automation. The design and construction of a prototype controller test bench, along with the PLC configuration, wiring diagrams, and control logic, constitute the significant contributions of this research. The proposed controller test bench’s performance is evaluated through similar condition simulations in the presence of disturbances induced by the reduced contributions of renewable energy sources, such as solar and wind. The results illustrate the effectiveness of the developed control algorithm implemented in the proposed controller, ensuring the stable operation of the microgrid. Consequently, this work advances the simulation-based validation of microgrid control algorithms and provides insights into the practical application of a PLC-based hardware test bench under various environmental conditions.

Nowadays, there is an increase in the demand for optimized services in urban environments. However, ground transportation in big urban centers has been facing challenges for many years (e.g., resilience and congestion) and new paradigms have been proposed, such as the Urban Air Mobility (UAM) concept. UAM aims to enhance the urban transportation system using manned and unmanned aerial vehicles (i.e., Electric Vertical Takeoff and Landing - eVTOL - vehicles). Although UAM offers many benefits (e.g., cost reduction and increase in transportation capacity), many challenges need to be faced to enable safe and efficient operations. Furthermore, trajectory planning is challenging in the National Airspace System (NAS) and UAM operations due to several factors. Finally, new initiatives concerning UAM trajectory planning can be accelerated with the support of an automatic what-if platform capable of evaluating trajectories feasibility and efficiency. This research aims to propose a simulation platform for enabling trajectory evaluation in UAM operations. This platform, named Trajectory-Based Urban Air Mobility Simulator (TUS), focuses on simulating trajectories in the urban aerial environment. TUS enables users to test new UAM algorithms (e.g., flow management strategies, real-time evaluation of maneuvers effectiveness, airspace configurations) and simulate both manned and unmanned vehicles. Furthermore, TUS operation relies on a set of inputs and evaluates the trajectories generated from efficiency and safety perspectives. This process is performed using a Discrete Event Simulation (DES) approach. The experiments performed showed that TUS can perform a realistic evaluation of UAM trajectories and can be effortlessly used to simulate hundreds of scenarios.

<div class="section abstract"><div class="htmlview paragraph">With the rapid development of multi-constellation GNSS, GNSS positioning has been widely applied in several fields. In urban environment, GNSS signals are vulnerable to external interference, and the centimeter-level accuracy of GNSS positioning cannot be obtained to extent the required for automatic driving. To improve the accuracy of position estimation in urban environments, the integration of GNSS and inertial navigation system was examined in this study, and the single-frequency, single-epoch positioning performance of single GNSS and GNSS/INS integrated navigation was analyzed through dynamic GNSS and IMU data collected from a vehicle. The experimental results showed that the efficiency ratio of GNSS data was 99.80% even when the GPS, GLONASS and BDS were used in an urban environment; moreover, the utilization rate of the GNSS data was only 97.37% because of low-accuracy observations caused by the complex urban environment. In the urban environment, the positioning accuracy of a single GNSS was reduced, and the integration of GNSS and inertial navigation system could improve the performance of single GNSS positioning. The results indicated that the performance of loosely coupled of GNSS/INS is affected if the positioning solution has severe bias because of incorrectly fixed ambiguity. Compared with other methods, the tightly coupled of GNSS/INS can obtain the optimal position solution in typical urban environments.</div></div>

The emerging subsea processing system described in this work, comprises several deepwater wells equipped with electric submersible pumps (ESPs) and one or more seabed booster pumps. This system provides efficient reservoir hydrocarbon recovery by maximizing pressure drawdown at the sandface. The in-well ESPs increase the pressure drawdown to improve production throughout the life of the reservoir, while the subsea booster pump lifts the combined production from all wells to reach the processing facilities at sea surface. This system integrates several production technologies to optimize performance, lower operating costs, and support reliable and safe operation. The Lower Tertiary trend (LTT) in the Gulf of Mexico (GOM) poses a number of documented challenges for flowing reservoir fluid from the sandface to surface facility. The key challenges are operations due to low permeability, high pressures, high temperatures, and water and well depths. The primary objective of this work was to document the feasibility of the subsea processing system and quantify its production performance for a typical LTT field. The work included development of a full field system layout and simulations of production performance for a range of reservoir and system assumptions. In addition, operational issues such as system stability, power balancing, and basic control methods were considered, including the use of transient simulations, to ensure a reliable and efficient operation of the system. These form the basis of a unified pump control methodology. To verify the impact of in-well ESP reliability on field performance, a comprehensive availability model was developed using reliability data for individual system components; ESP reliability, ESP intervention time, and rig deployment time were varied to determine their impact on overall system availability. The results of the availability model were then combined with the steady-state production results to define production availability and calculate a range of internal rate of return (IRR) values for a typical LTT field development. Utilization of the system showed enhancement in oil recovery in the range of 20 to 50% over use of a seabed boosting pump alone and substantial improvement in total liquid and oil gain as compared to natural lift. The system resulted in very satisfactory IRR and achieved production availability targets by using alternatively deployed ESPs. Moderate improvement in in-well ESP reliability combined with shorter rig mobilization time for intervention shows significant improvement in production availability. In total, the combination of seabed boosting pumps and in-well ESPs should be considered as a viable method of enhancing recovery from challenging deepwater subsea fields such as those of the LTT in GOM. The unified pump control methodology is the key to safe and reliable operation of the system. The current work presents an approach on how to operate ESPs safely, by minimizing transient responses and shifting total operating load as much as possible to the seabed pumps, thereby reducing stress on the ESPs. Furthermore, the development of an enhanced production availability model of the system quantifies the production performance for a variety of field scenarios and subsystem behavior.

Operations involving small Unmanned Aerial Systems (sUAS) in urban environments are occurring ever more frequently as recognized applications gain acceptance, and new use cases emerge, such as urban air mobility, medical deliveries, and support of emergency services. Higher demands in these operations and the requirement to access urban airspace present new challenges in sUAS operational safety. The presence of Detect and Avoid (DAA) capability of sUAS is one of the major requirements to its safe operation in urban environments according to the current legislation, such as the CAP 722 in the United Kingdom (UK). The platform or its operator proves a full awareness of all potential obstacles within the mission, maintains a safe distance from other airspace users, and, ultimately, performs Collision Avoidance (CA) maneuvers to avoid imminent impacts. Different missions for the defined scenarios are designed and performed within the simulation model in Software Tool Kit (STK) software environment, covering a wide range of practical cases. The acquired data supports assessment of feasibility and requirements to real-time processing. Analysis of the findings and simulation results leads to a holistic approach to implementation of sUAS operations in urban environments, focusing on extracting critical DAA capability for safe mission completion. The proposed approach forms a valuable asset for safe operations validation, enabling better evaluation of risk mitigation for sUAS urban operations and safety-focused design of the sensor payload and algorithms.

Background The main strategic goal of Gazprom is to preserve the stability of the company for the long term. The company has a unique system - Unified Gas Supply System, which allows to react quickly to any changes in its subsystems and the system as a whole. Aims and Objectives One of the most important and necessary tasks is the on-time maintenance of the gas mains and extension of the reliable and safe operation lifetime. Conclusions The paper contains the concept of maintaining and extending the safe and reliable operation lifetime of the linear part of main gas pipelines and the methodology of step-by-step implementation of the concept, and provides scientific and technical solutions to improve the efficiency of repair and construction works at the present time. Threre were proposed new and promising scientific and technical solutions to prolong the safe and reliable operation of existing gas mains.

Pulping machines are an integral part of production lines for the processing fruits and vegetables. To meet the ever-growing demand for these agricultural products, it is necessary to introduce innovative solutions to modernize equipment not only for increasing its productivity but also for ensuring its safety. The article proposes a pulping machine that helps to increase the productivity by using the entire area of the sieve drum. The productivity also depends on reliable and safe equipment operation, elimination of downtime during product pulping. One of the main factors affecting the reliable and safe operation is the pressure of pulped product on the walls of the sieve drum, and this pressure depends on the product density. It has been experimentally shown that the density of pulped product can vary significantly even for different varieties of vegetable marrow. As the calculations show, in this case the pressure inside the sieve drum of the pulping machine changes considerably (more than 10%). Therefore, the density of the product should be taken into account when calculating the design parameters of the pulping machine; it helps to ensure its reliable and safe operation and hence to reduce the probability of downtime and to improve the productivity.

GaN power HEMTs are known to offer high switching speed, low on-resistance and much better FOM when compared to their silicon counterparts. However, the ability to operate with high power density in a smaller form factor presents new challenges for reliable and robust operation. Traditional gate driver designs for silicon-based power devices are catered to lower frequencies with large tolerance on the gate voltage swing. They do not adequately address some of the reliability issues that are unique to GaN power transistors. This talk will provide a quick review on the gate driving requirements and limitations for GaN power HEMTs. This is followed by a survey of novel smart gate driving techniques that can further exploit the performance and enhance the reliability of GaN power devices. Topics to be covered include intelligent gate driving schemes such as active gate driving, dead time optimization, and current balancing. Emphasis will be given to designs that can be integrated and those that can monitor the devices for optimum performance and safe operation. Protection features such as short-circuit detection, gate overvoltage prevention, temperature monitoring and compensation will also be discussed. Monolithic integration of power GaN ICs is an exciting area of development with increasingly sophisticated designs reported in recent years. Fully integrated GaN building blocks and state of the art designs will be addressed.

The Impact of Commercial Parking Utilization on Cyclist Behavior in Urban Environments