INTERNATIONAL DEVELOPMENT AND VALIDATION OF A DISTRIBUTED SIMULATION FOR NAVAL SHIP REPLENISHMENT AT SEA

Navies from Canada, France, Germany, Italy, and the United Kingdom collaborated to develop and validate a distributed simulation of ship replenishment at sea. The simulation models the seaway, ship motions including hydrodynamic interaction effects between ships, and the transfer of a solid payload between ships using replenishment gear. The simulation was developed using the High Level Architecture (HLA), which facilitates sharing of data and synchronization of simulation time among software components on networked computers. Simulation results were validated using experimental data. The project demonstrated successful application of distributed simulation to complex naval platform systems. Lessons learned are shared for several areas, including seaway modelling, ship hydrodynamic interaction, and planning of model tests and sea trials for simulation validation.

A distributed simulation study to investigate pedestrians’ head-turning behaviour when crossing in response to automated and human-driven vehicles displaying different braking patterns

This distributed simulator study investigated pedestrians’ head-turning behaviour during a series of road crossings in a CAVE-based pedestrian simulator. Pedestrians were required to cross the road in front of an approaching vehicle, the kinematic behaviour of which was either programmed by the simulation to depict an automated vehicle (AV) or controlled by a human driver (HD), via a connected (hidden) desktop driving simulator. A within-participant experimental design was used with twenty-five pairs of participants (a pedestrian and a driver). For each trial, pedestrians had to decide whether to cross in front of the HD/AV, which was instructed (or programmed) to yield (or not) to the pedestrian. For the AV trials, two braking patterns were included: a hard-braking AV (AVHB, deceleration rate = 3.2 m/s2, stopping distance = 12 m from pedestrian) and soft-braking (AVSB, deceleration rate = 2.5 m/s2, stopping distance = 4 m from pedestrian). Pedestrians’ head-turning frequency and the change in head-turning angle, were calculated for each condition, both before a crossing was initiated, and during the actual road crossing. Results showed a significant increase in head-turning behaviour in the last 2 seconds before a crossing initiation in the yielding trials, in line with a ‘last-second check’ reported in observations of real-world crossings (Hassan, Geruschat, & Turano, 2005). The vehicle’s braking behaviour and stopping distance were the most important factors affecting pedestrians’ head-turning patterns during the crossing, with the least head-turning behaviour seen in the AVSB condition, compared with AVHB and HDB trials. This suggests that a closer stopping distance for the AV was associated with less confusion for the pedestrian, although this condition was also associated with the longest crossing initiation time. In contrast, the highest number of head-turnings were seen for the human-driven vehicle, which, on average, yielded about 40 m away from the participants, enabling a much faster crossing initiation. Overall, the shortest crossing initiation time (~ 1 sec) and highest head-turning behaviour were seen in the non-braking conditions, where participants crossed as quickly as the circumstances allowed. These results provide new insights about the use of VR simulators for understanding pedestrians’ crossing behaviour in response to different vehicle kinematics. They also extend our knowledge of pedestrian cues for the development of suitable sensors in future automated vehicles, which should help with providing a more seamless interaction between AVs and other road users in mixed traffic settings.

Review on the Quality Attributes of an Integrated Simulation Software for Weapon Systems

This paper describes the quality attributes of an integrated simulation software for weapon systems named Advanced distributed simulation environment(AddSIM). AddSIM is developed as a key enabler for Defense Modeling & Simulation(M&S) systems which simulate battlefields and used for battle experiments, analyses, military exercises, training, etc. AddSIM shall provide a standard simulation framework of the next Defense M&S systems. Therefore AddSIM shall satisfy not only functional but also quality requirements such as availability, modifiability, performance, testability, usability, and others. AddSIM consists of operating softwares of hierarchical components including graphical user interface, simulation engines, and support services(natural environment model, math utility, etc.), and separated weapon system models executable on the operating softwares. The relation between software architectures and their quality attributes are summarized from previous works. And the AddSIM architecture and its achievements in the aspect of quality attributes are reviewed.

An Original Distributed Simulation Method Applied to the Advanced Nuclear Power Plant Control Technology Hardware-in-the-Loop Simulation Verification Platform

Hardware-in-the-loop (HIL) simulation technology, where the part of a system to be verified adopts real objects, is one of the important methods for the research of advanced nuclear power plant (NPP) instrumentation and control (I&C) technology. With the development of advanced NPP I&C technology, especially the multi-module NPP technology, the HIL simulation technology is facing the challenge of communication signals booming and model extension to deal with the requirement of modules increasing and thermal-electricity generation. Driven by the above requirement of research and engineering, it is necessary to develop a novel HIL simulation technology that has well flexible scalability and avoids the high computational burden of the distributed control system (DCS). In this paper, an original distributed simulation method applied to the transformation extension of the NPP I&C HIL simulation verification platform is proposed. The initial opinion of the method is deploying a third-party system utilized for numerical simulation and form a close loop with DCS by network communication. With the support of third-party equipment represented by the real-time target machine, the functions of the system can be flexibly expanded through the MODBUS series protocol, and algorithms with high sampling frequency requirements can be deployed. The method has the characteristics of economical communication consumption, standardized and reliable communication protocol, and flexible downloading models and algorithms mean. Aside from this, due to the relative independence from DCS, the distribute simulation method is promising to be an original platform for verifying the technology advanced control or fault diagnosis in addition to DCS computing servers.