Jsim和simpack

jsim和simpack是常用的模拟工具，simpack将很多种模型整合到了一起，提供多种语言的版本，使用起来比较方便；jsim是个很强大的模拟工具，最适合用来模拟网络，它提供外部TCL语言接口，简单地使用TCL脚本就可以模拟出一个很复杂的网络，下面是其官方网站链接，供网友参考：



以下是jsim的简单介绍：

J-Sim (formerly known as JavaSim) is a component-based, compositional simulation environment. It has been built upon the notion of the Similar to , , or the basic entity in J-Sim is components, but unlike the other component-based software packages/standards, components in J-Sim are autonomous and are realization of software ICs (see the white paper "" for details).

The autonomous component architecture mimics the IC design architecture in the closest possible way. The behavior of J-Sim components are defined in terms of contracts (in much the same way IC chips are defined in the specification in the cookbook) and can be individually designed, implemented, tested, and incrementally deployed in a software system.  A system can be composed of individual components in much the same way a hardware module is composed of IC chips. Moreover, components can be plugged into a software system, even during execution.

For the purpose of network modeling and simulation, we have defined, on top of the autonomous component architecture, a   The model defines the generic structure of a node (either an end host or a router) and the generic network components, both of which  can then be used as base classes to implement protocols across various layers.  Although the model is derived by featuring out the common attributes of network entities in the current best-effort Internet, it is general enough to accommodate other network architectures, such as the IETF differentated services architecture, the mobile wireless network architecture, and the WDM-based optical network architecture. 

J-Sim has been developed entirely in .  This, coupled with the autonomous component architecture, makes J-Sim a truly platform-neutral, extensible, and reusable environment.  J-Sim also provides a script interface to allow integration with different script languages such as , Tcl, or . In the current release,  we have fully integrated J-Sim with a Java implementation of the Tcl interpreter (with the Tcl/Java extension), called . So, similar to ns-2, J-Sim is a dual-language simulation environment in which classes are written in Java (for ns-2, in C++) and "glued" together using Tcl/Java.  However, unlike ns-2, classes/methods/fields in Java need not be explicitly exported in order to be accessed in the Tcl environment.  Instead, all the public classes/methods/fields in Java can be accessed (naturally) in the Tcl environment.

以下是simpack的简单介绍，其实它的用途不仅仅限于这些，完全可以用的更为广泛的，其所支持的模型可以用来模拟机械、网络、行为等等。

SIMPACK is a multi-body simulation software used for mechanical and mechatronic system design。

SIMPACK is a general Multi-Body Simulation Software which is used to aid engineers in the analysis and design of mechanical and mechatronic systems.

From initial concept designs, through to production and redesigns, SIMPACK is used to help engineers fully comprehend and optimise systems, vastly reduce the need for physical prototyping, reduce time-to-market and to improve product quality and lifespan. In essence SIMPACK enables manufacturers to gain a competitive edge by offering the ability create high quality products in a time and materially efficient manner thus reducing overall costs in design, production and maintenance.