Myeong-Jo Son

Modeling and simulation of target motion analysis for a submarine using a script-based tactics manager

Various types of simulation are required for underwater vehicles such as submarines or torpedoes. These include engineering-level simulations for predicting the performance and engagement-level simulations for examining the effectiveness of certain tactics. For this reason, a tactics manager that can change the behavior of a simulation model according to tactics defined outside the model is needed. This paper describes a tactics manager that supports a scripting language that can represent various tactics and can help users to easily define external input tactics. Python and Lua, representative scripting languages, are compared and analyzed from the viewpoint of a tactics manager, and a tactics manager using those script languages is implemented. A target motion analysis simulation of the engagement between a submarine and a surface ship is conducted to demonstrate the effectiveness of the tactics manager. We generated a simulation model based on the Discrete Event System Specification formalism and provided it with an interface to the tactics manager.

Maneuvering control simulation of underwater vehicle based on combined discrete-event and discrete-time modeling

When designing or acquiring underwater vehicles such as submarines and torpedoes, it is necessary to predict their performance precisely and perform tests repeatedly using modeling and simulation at both the engineering level and the tactical engagement level. For simulation performed for analysis purposes at the engineering level, which requires a considerable amount of computation power, a discrete-time system simulation that computes significant values at every single unit time using the established mathematical model or engineering model is mainly employed. To simulate a complex or complicated task such as a traffic analysis or tactical measure of effectiveness (MOE) analysis at the engagement level, it is appropriate to use a discrete-event system simulation that causes transition between model states through the triggering of events on the basis of the passing of messages between simplified mathematical models coupled in various ways. In this paper, we studied a maneuvering control of underwater vehicle from the perspective of a combined discrete-event and discrete-time system simulation; the simulation model is established on the basis of discrete-event system specification (DEVS) formalism, which is a representative modeling formalism of a discrete-event system simulation. In detail, the simulation includes DEVS modeling implementations of simulation execution time control and discrete-time step size control in real time at the time of performing a discrete-time system simulation for the purpose of three-dimensional visualization or carrying out a performance analysis using the DEVS model. This hybrid approach makes possible to build a simulation-based expert system which supports the decision making for the acquisition of an underwater vehicle.

Torpedo evasion simulation of underwater vehicle using fuzzy-logic-based tactical decision making in script tactics manager

An underwater vehicle such as a submarine or a torpedo is a complex and complicated weapon system composed of various systems and subsystems. Usually, it takes around 10years, a substantial amount of money, and many research and development resources to complete the development of an underwater vehicle, right from the concept design to the mass production. Recently, in order to reduce the number of trial-and-error instances required for verifying the operation of an underwater vehicle, modeling and simulation (M&S) has been investigated and applied to an engineering-level simulation to analyze the performance of a system and a subsystem and to an engagement-level simulation to analyze the tactical and operational effectiveness. In this paper, we introduce a method for applying fuzzy logic to the tactical decision making of an underwater vehicle in an engagement-level simulation. In the scenario of an engagement between a light torpedo pursuing a submarine and the submarine attempting to evade the attack, the evasion methods for the submarine are modeled in fuzzy logic after tacticalization. For the simulation, we modeled a light torpedo and a submarine on the basis of DEVS (Discrete Event System Specification). Further, when a tactical decision had to be taken, the submarine model calls the tactics manager implemented outside of the model and passes its own state variables, which are necessary for tactical decision making, to the tactics manager. The tactics manager used in the tactical decision making process supports Lua and the Python scripting languages and is self-implemented. The tactics description of the submarine was implemented using Python scripting grammar and stored as a Python file (*.py) to be inputted to the tactics manager. As the simulation results, we present the implemented fuzzy Python tactic description file of the submarine evasion tactics and the possibilities of submarine survival according to the tactics as a comparison. Finally, as the fundamental research on the application of artificial intelligence to the tactical decision making method of the model used in the engagement-level simulation, this work suggests the fuzzy-based tactics description method and presents the detailed procedures for the various actions, and their adopting effectiveness.

Implementation of a Tactic Manager for the Simulation of a Target Motion Analysis between a Submarine and a Surface Ship Warfare

A tactic manager which can change the behavior of a simulation model according to the tactics defined outside of the model has been studied and implemented. Based on DEVS(discrete event system specification) formalism, we generated a simulation model which is equipped with the interface to the tactic manager. To demonstrate the effectiveness of the tactic manager, a target motion analysis in the warfare between a submarine and a surface ship is simulated.

High-level Discrete-event Modeling-based Business Process Simulation for the Scheduling of the Ship Hull Production Design

For the scheduling and the job assignment of the ship hull production design which is a process-based work, we suggest the simulation-based scheduling using the discrete-event-based business process simulation. First, we analyze the ship hull production design process from the perspective of a job assignment to make it into the simulation model using DEVS (Discrete Event System Specification) which is the representative modeling method for a discrete-event simulation. Based on the APIs of the open-source discrete-event simulation engine, we implement the simulation using the Groovy script. We develop the scenario generator in which the user defines detail information of the construction drawing and its member blocks, and design engineers information, and the various setting for the simulation including the job assignment strategy. We use the XML files from this scenario generator as inputs of simulation so that we can get simulation result in forms of Gantt chart without changes of the simulation model.

Job Assignment Simulation of Ship Hull Production Design in Consideration of Mid-Term Schedule

In this paper, we analyze the procedure of the design manager for the enhancement of the hull production design process by use of the simulation method. Normally, design manager assigns design jobs according to various methods and estimates the corresponding results. When the construction drawing which is the output of the detail design where a design is dealt by zones, the design manager identifies blocks and analyzes their work difficulties, and assigns jobs to design engineers who are different in capabilities. These processes including the design engineer who can be modeled with man-hours evaluation model are represented in detail as a simulation model. As the high-level modeling for the discrete-event system, we use Event Graph model. And we implemented the simulation using Simkit which is open simulation engine for the discrete-event system. We made the simulation scenario to be written by a user in the scenario generator which is separated from the simulation model, and made the simulation result to be visualized in the form of Gantt chart in a Web. In the scenario of the irregular issuance for various construction drawings which contain different numbers of blocks, we performed the Monte-Carlo simulation according to various assignment methods to find the assignment result that satisfies the mid-term schedule.

Development of a simple model for batch and boundary information updation for a similar ship’s block model

In early 2000, large domestic shipyards introduced shipbuilding 3D computer-aided design (CAD) to the hull production design process to define manufacturing and assembly information. The production design process accounts for most of the man-hours (M/H) of the entire design process and is closely connected to yard production because designs must take into account the production schedule of the shipyard, the current state of the dock needed to mount the ship’s block, and supply information. Therefore, many shipyards are investigating the complete automation of the production design process to reduce the M/H for designers. However, these problems are still currently unresolved, and a clear direction is needed for research on the automatic design base of manufacturing rules, batches reflecting changed building specifications, batch updates of boundary information for hull members, and management of the hull model change history to automate the production design process. In this study, a process was developed to aid production design engineers in designing a new ship’s hull block model from that of a similar ship previously built, based on AVEVA Marine. An automation system that uses the similar ship’s hull block model is proposed to reduce M/H and human errors by the production design engineer. First, scheme files holding important information were constructed in a database to automatically update hull block model modifications. Second, for batch updates, the database’s table, including building specifications and the referential integrity of a relational database were compared. In particular, this study focused on reflecting the frequent modification of building specifications and regeneration of boundary information of the adjacent panel due to changes in a specific panel. Third, the rollback function is proposed in which the database (DB) is used to return to the previously designed panels.

Scheduling and Cost Estimation Simulation for Transportation and Installation of the Offshore Monopile Wind Turbines

For reasons such as global warming, depletion of fossil fuels and the danger of nuclear energy the research and development of renewable energy is actively underway. Wind energy has advantages over another renewable energy in terms of location requirements, energy efficiency and reliability. Nowadays the research and development area is expanded to offshore because it can supply more wind reliability and free from noise pollution. In this study, the monopile offshore wind turbine transportation and installation (T&I) process are investigated. In addition, the schedule and cost for the process are estimated by discrete event simulation. For the simulation, simulation models for various means of T&I are developed. The optimum T&I execution plan with shortest duration and lowest cost can be found by using different mission start day and T&I means.

AVEVA Marine Scheme-based Modeling for Reuse of Ship Hull Block Model

For the reuse of the existing 3D block model of a ship, we analyze the hull modeling process using AVEVA Marine which is a representative CAD (Computer-Aided Design) system for the shipbuilding. In the AVEVA Marine environment where the design engineer makes 3D model on the 2D view that is so-called 2.5D, it cannot be possible to copy to reuse the block model just simply copying the 3D feature model itself like in the general mechanical CAD system or Smart Marine 3D which are on the basis of the 3D model representation. In this paper, we analyze the scheme file where the 3D model is defined in AVEVA Marine so that we develop the program for the block copy and the translation using this scheme file. It is significant that this program can be immediately available as a real-world application on the AVEVA Marine environment.

The DEVS-based Detailed Implementation Method of the Command and Fire Control System for the Underwater Vehicle DEVS-HLA Simulation in the Engagement Level

To perform the engagement level simulation between the underwater vehicle model and the surface model those are constituted with various systems/ sub-systems, we implemented four different federates as a federation according to the IEEE 1516 HLA (High Level Architecture) protocol that is the international standard in the distributed simulation. Those are CFCS (Command and Fire Control System) federate, motion federate, external entities (torpedos, countermeasure and surfaceship) federate, and visualization federate that interacts with OSG (Open Scene Graph)-based visualization rendering module. In this paper, we present the detailed method about the model constitution for discrete event simulation in the distributed environment. For the sake of this purpose, we introduce the DEVS (Discrete Event System Specification)-HLA-based modeling method of the CFCS federate that reflects not only the interations between models, but also commands from user and tactics manager that is separated from the model. The CFCS federate makes decisions in various missions such as the normal diving, the barrier misision, the target motion analysis, the torpedo launch, and the torpedo evasion. In the perspective of DEVS modeling, the CFCS federate is the coupled model that has the tactical data process model, command model and fire control model as an atomic model. The message passing and time synchronization with other three federates are settled by the RTI (Runtime Infrastructure) that supports IEEE 1516. In this paper, we provides the detailed modeling method of the complicated model that has hierarchical relationship such as the CFCS system in the submarine and that satisfies both of DEVS modeling method for the discrete event simulation and HLA modeling method for the distributed simulation.