1.8 Overview of the Kotlin Simulation Library
The KSL (a Kotlin Simulation Library) is a simulation library for Kotlin The KSL’s current version has packages that support random number generation, statistical collection, basic reporting, and discrete-event simulation modeling via both the event-view and the process-view.
The purpose of the KSL is to support education and research within simulation. Current simulation languages hide the implementation details of the workings of a simulation. As such, students exposed to a simulation language such as (ProModel, Arena, and AutoMod, etc.) are able to learn the practice of simulation without having a detailed understanding of the fundamental mechanisms that enable the technology. This has both advantages and disadvantages. The advantage is that more engineers are capable of using and applying simulation technology to improve systems. The disadvantage is that their modeling abilities depend heavily on a particular software package and simulation modeling has the potential to become a black-box technology. The use of commercial simulation software programs results in proprietary models that have limited interoperability. Many users of commercial simulation software programs can build complicated models, but may have limited understanding of how the simulation actually works.
When teaching simulation, especially at the undergraduate level, simulation languages enable students with introductory programming skills to model systems and perform experiments. Within a typical introductory semester course on simulation it is possible to cover the basics of simulation (random numbers, modeling, and statistical analysis) along with the coverage of a tool (Arena, ProModel, AutoMod, etc.) It is difficult to teach students how simulation works based on a general purpose programming language due to the reduced emphasis on more advanced programming skills especially for non-computer science majors. The KSL assists in bridging this gap by providing a standard library in Kotlin for simulation modeling. One of the fundamental design goals of the KSL is to clearly demonstrate how one can implement the fundamental mechanisms that enable simulation technology. By studying the implementation details students will gain a deeper understanding of how simulation works. They will become better simulation modelers, practitioners, and users of commercial simulation languages.
The KSL also supports research within simulation. Naturally, the KSL can be used as a modeling tool to simulate complex systems. Simulators, such as a Supply Chain Simulator, can be built based on the KSL framework. In addition, the design of the KSL provides a framework for the testing of simulation artifacts through a well-defined class and interface hierarchy. The structure of the KSL permits the easy switching of various components within a simulation, the event calendar, random number generator, statistics, etc. For example, the efficiency of different event calendars can be tested by providing an event calendar to the KSL that implements the CalendarIfc interface. Different algorithms can be “plugged into” the framework for testing.
This book presents an overview of a simulation library for Kotlin (KSL). The library is divided into packages (calendar, controls, modeling, observers, simulation, and utilities). As necessary, these packages may contain sub-packages, which implement various aspects of the library. The KSL is organized as two open source projects: KSLCore and KSLExamples. Each of these projects is further organized into packages.
KSLCore - ksl is the main package that holds all sub-packages
- calendar - The calendar package implements classes that provide event calendar processing
- simulation - The simulation package implements the main classes involved in constructing and running simulation models.
- modeling - The modeling package is the heart of the KSL. In the modeling package, supporting model elements such as queues, resources, variables, responses, etc. are implemented. This package will be discussed in detail in this document.
- observers - The observers package provides support classes for observing model elements during the simulation run. The KSL is designed to allow each model element to have observers attached to it thereby implementing the classic Observer pattern. Observers can be used to collect statistics, write output to files, display model element state, etc.
- utilities - The utilities package provides support classes that are used by the KSL. The random, statistics, reporting, and database related sub-packages will be discussed in this document.
- observers - The observers package provides support classes for observing model elements during the simulation run. The KSL is designed to allow each model element to have observers attached to it thereby implementing the classic Observer pattern. Observers can be used to collect statistics, write output to files, display model element state, etc.
KSLExamples - examples is the main package that holds all sub-packages
- book - packages containing the examples of this book
- general - examples of the use of various KSL constructs that are not necessarily discussed within the book.
The purpose of the KSL is to provide support for the development of discrete-event simulation programs within Kotlin. This document provides and overview of the functionality and use of the classes found within the KSL. Additional information is available through the documentation API. We begin our discussion in the next chapter with the utilities package within the KSLCore. These support packages can be used independently of building discrete-event simulation models.