Evaluation of software tools in performing advanced evacuation analyses for passenger ships

As safety regulations for passenger ship design continue to advance, so does the need for evacuation analysis tools to simulate the evacuation process. Currently the IMO requires an evacuation analysis for all new passenger ships in one of two ways: a simplified analysis or an advanced analysis. The simplified analysis takes a macroscopic view of the problem, treating the evacuees as particles in a fluid, flowing to their muster stations through corridors and doors as if they were pipes and valves. On the other hand, the advanced analysis takes a more microscopic approach, treating each evacuee as an individual with their own behaviour and decision making. However, as crowd simulation on passenger ships is a relatively young field of study, there is no clear consensus on the best way to perform this advanced analysis and therefore the guidelines are left more open ended. Consequently, there are several software suites that perform the analysis in different ways. This study aims to evaluate and better understand two different software packages, Evi and Pathfinder, which are capable of performing an advanced evacuation analysis. To do this, the same evacuation scenario on the same Main Vertical Zone (MVZ) of a RoPax ferry was simulated on both software in order to see how the differences in approaching the modelling affected both the numerical results and the user experience, including the time taken to build and run the analysis. These results were further compared with those obtained from a simplified analysis. Despite differences in how the reaction times were distributed, the total completion times measured were very similar, falling within the acceptance criteria set for this study. However, the user experience is where the largest differences between the two software became apparent. While Pathfinder had a more feature-rich toolset to build the geometry, the fact that Evi is purpose built to perform evacuation analyses of passenger ships is apparent in its preset IMO cases and batch running capabilities, providing a clear time advantage in performing the task

IMPROVE - Innovative Modelling Approaches for Production Systems to Raise Validatable Efficiency

This open access work presents selected results from the European research and innovation project IMPROVE which yielded novel data-based solutions to enhance machine reliability and efficiency in the fields of simulation and optimization, condition monitoring, alarm management, and quality prediction

Discrete Event Simulations

Considered by many authors as a technique for modelling stochastic, dynamic and discretely evolving systems, this technique has gained widespread acceptance among the practitioners who want to represent and improve complex systems. Since DES is a technique applied in incredibly different areas, this book reflects many different points of view about DES, thus, all authors describe how it is understood and applied within their context of work, providing an extensive understanding of what DES is. It can be said that the name of the book itself reflects the plurality that these points of view represent. The book embraces a number of topics covering theory, methods and applications to a wide range of sectors and problem areas that have been categorised into five groups. As well as the previously explained variety of points of view concerning DES, there is one additional thing to remark about this book: its richness when talking about actual data or actual data based analysis. When most academic areas are lacking application cases, roughly the half part of the chapters included in this book deal with actual problems or at least are based on actual data. Thus, the editor firmly believes that this book will be interesting for both beginners and practitioners in the area of DES

Nondeterministic hybrid dynamical systems

This thesis is concerned with the analysis, control and identification of hybrid dynamical systems. The main focus is on a particular class of hybrid systems consisting of linear subsystems. The discrete dynamic, i.e., the change between subsystems, is unknown or nondeterministic and cannot be influenced, i.e. controlled, directly. However changes in the discrete dynamic can be detected immediately, such that the current dynamic (subsystem) is known. In order to motivate the study of hybrid systems and show the merits of hybrid control theory, an example is given. It is shown that real world systems like Anti Locking Brakes (ABS) are naturally modelled by such a class of linear hybrids systems. It is shown that purely continuous feedback is not suitable since it cannot achieve maximum braking performance. A hybrid control strategy, which overcomes this problem, is presented. For this class of linear hybrid system with unknown discrete dynamic, a framework for robust control is established. The analysis methodology developed gives a robustness radius such that the stability under parameter variations can be analysed. The controller synthesis procedure is illustrated in a practical example where the control for an active suspension of a car is designed. Optimal control for this class of hybrid system is introduced. It is shows how a control law is obtained which minimises a quadratic performance index. The synthesis procedure is stated in terms of a convex optimisation problem using linear matrix inequalities (LMI). The solution of the LMI not only returns the controller but also the performance bound. Since the proposed controller structures require knowledge of the continuous state, an observer design is proposed. It is shown that the estimation error converges quadratically while minimising the covariance of the estimation error. This is similar to the Kalman filter for discrete or continuous time systems. Further, we show that the synthesis of the observer can be cast into an LMI, which conveniently solves the synthesis problem

Formal Specification and Verification for Automated Production Systems

Complex industrial control software often drives safety- and mission-critical systems, like automated production plants or control units embedded into devices in automotive systems. Such controllers have in common that they are reactive systems, i.e., that they periodically read sensor stimuli and cyclically execute the same program to produce actuator signals. The correctness of software for automated production is rarely verified using formal techniques. Although, due to the Industrial Revolution 4.0 (IR4.0), the impact and importance of software have become an important role in industrial automation. What is used instead in industrial practice today is testing and simulation, where individual test cases are used to validate an automated production system. Three reasons why formal methods are not popular are: (a) It is difficult to adequately formulate the desired temporal properties. (b) There is a lack of specification languages for reactive systems that are both sufficiently expressive and comprehensible for practitioners. (c) Due to the lack of an environment model the obtained results are imprecise. Nonetheless, formal methods for automated production systems are well studied academically---mainly on the verification of safety properties via model checking. In this doctoral thesis we present the concept of (1) generalized test tables (GTTs), a new specification language for functional properties, and their extension (2) relational test tables (RTTs) for relational properties. The concept includes the syntactical notion, designed for the intuition of engineers, and the semantics, which are based on game theory. We use RTTs for a novel confidential property on reactive systems, the provably forgetting of information. Moreover, for regression verification, an important relational property, we are able to achieve performance improvements by (3) creating a decomposing rule which splits large proofs into small sub-task. We implemented the verification procedures and evaluated them against realistic case studies, e.g., the Pick-and-Place-Unit from the Technical University of Munich. The presented contribution follows the idea of lowering the obstacle of verifying the dependability of reactive systems in general, and automated production systems in particular for the engineer either by introducing a new specification language (GTTs), by exploiting existing programs for the specification (RTTs, regression verification), or by improving the verification performance

Computer Aided Verification

This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book

The integration of human factors, operability and personnel movement simulation into the preliminary design of ships utilising the Design Building Block approach

This thesis presents the feasibility, advantages and impact on Preliminary Ship Design of an approach to integrate ship configurational design with the modelling and simulation of a range of crewing issues, such as operations and evacuation. Integrating personnel movement simulation into preliminary ship design introduces the assessment of onboard operations at the front-end of the design process, informing the design and enabling improved operability while the design is still amenable to changes. The approach to accomplish this integration is discussed with the aim of informing all parties involved in the design of ships with regard to the main aspects of personnel operability and on board safety. The research was undertaken as part of a three years research project funded by the Engineering and Physical Sciences Research Council (EPSRC) entitled “Guidance on the Design of Ships for Enhanced Escape and Operation”. The project aimed at bringing together the University of Greenwich developed “maritimeEXODUS” personnel movement simulation software and the SURFCON implementation in the PARAMARINE suite of the Design Building Block approach to Preliminary Ship Design, which originated with the UCL Ship Design Research team. The approach and procedural implications of integrating personnel movement simulation into the preliminary ship design process are presented through a series of SURFCON ship design case studies. With the UK Ministry of Defence as the industrial partner to the project, this study on “design for operation” concentrates on naval vessels, which provide excellent examples of complex environments. Design studies, based on the Royal Navy Type 22 Batch III Frigate design, were analysed using PARAMARINE, maritimeEXODUS and bespoke interface software produced by the candidate. Technical aspects of the development of the interface software are discussed from a procedural perspective, focusing on integration and usability issues. The discussion addresses alternative options to visualising the simulation results and how to integrate into a ship design model a minimum level of detail sufficient to conduct simulations able to inform the designer, while retaining the flexibility the design requires in early stages design. The thesis concludes by summarising the opportunities that integrating operational simulation into preliminary ship design opens up for the future practice of ship design, contributing to the debate on the nature of ship design and of Computer Aided Preliminary Ship Design

Reinforcement Learning

Brains rule the world, and brain-like computation is increasingly used in computers and electronic devices. Brain-like computation is about processing and interpreting data or directly putting forward and performing actions. Learning is a very important aspect. This book is on reinforcement learning which involves performing actions to achieve a goal. The first 11 chapters of this book describe and extend the scope of reinforcement learning. The remaining 11 chapters show that there is already wide usage in numerous fields. Reinforcement learning can tackle control tasks that are too complex for traditional, hand-designed, non-learning controllers. As learning computers can deal with technical complexities, the tasks of human operators remain to specify goals on increasingly higher levels. This book shows that reinforcement learning is a very dynamic area in terms of theory and applications and it shall stimulate and encourage new research in this field