Frequently Asked Questions

General Questions

Compatibility Questions

Technical Questions

General Questions

What is AJEM?
 
AJEM stands for Advanced Joint Effectiveness Model.

AJEM is a lethality, vulnerability, and endgame computer simulation code capable of analyzing one or more threats attacking a single rotary-wing or fixed-wing aircraft or gound-mobile target. It combines elements of target modeling, threat modeling, encounter kinematics, generation of weapon burst points, propagation of damage mechanisms to the target, damage mechanism / target interaction (penetration, fire, blast, etc.), target system relationships (functionality, redundancies, etc.), and target remaining capability or loss of function.

AJEM was designed to be a DoD standard computer simulation for evaluating the lethality and terminal effectiveness of munitions and the vulnerability of aircraft, missiles, and ground-mobile systems, including battle damage assessment and repair (BDAR). AJEM produces results that are applicable during all phases of weapon system acquisition from research, design, and development to production test and evaluation. AJEM produces results which are observable / measurable for testing and real-world events.

AJEM is designed to run in conjunction with BRL-CAD® and the MUVES environment, capitalizing on work already performed by ARL/SLAD.

Why AJEM?
 
Over the years, a number of vulnerability codes have been developed to address various aspects of vulnerability. Many of these codes were developed decades ago using outdated programming languages and techniques. A need existed for a modern, standardized computer simulation for performing vulnerability and endgame analyses.
 
What's MUVES?
 
MUVES stands for Modular Unix-based Vulnerability Estimation Suite. MUVES is a library of standardized "packages" (or related functions) developed by ARL/SLAD to aid in the development of vulnerability analysis models, or "methods". MUVES provides a framework of tools and utilities used in most vulnerability applications such as raytracing, penetration equations, and memory management.
 
Do I need to know MUVES to run AJEM?
 
Yes and No.
 
Technically, you don't need to know anything about MUVES in order to run AJEM. AJEM is executed from a command line just like any other program or application. However, developing an understanding of MUVES and associated input files will increase your understanding of the underlying code.
 
What are SAFE and S2?
 
SAFE is the approximation method, or model, under the MUVES environment which represented the starting point for AJEM. Since that time, SAFE was combined with the SQuASH model under MUVES and renamed S2. The capabilities added to SAFE to support AJEM have been integrated back into S2. The Vulnerability/Lethality module in AJEM 1.0 (and later versions) is actually the ARL S2 code.
 
How do I obtain a copy of AJEM?
 
Use the order form on the AJEM website (www.ajem.com) to request a copy of AJEM.

Compatibility Questions

Can I use my old COVART input decks?
 
Yes.
 
There is a COVART to AJEM conversion utility provided with AJEM that will convert a large portion of the information contained in COVART4-formatted input files into MUVES (and thus, AJEM) compatible format. See the AJEM User/Analyst Manual for details on the COVART Input File Converter.
 
Can I use my existing FASTGEN target descriptions?
 
Yes.
 
BRL-CAD 5.1 (and later versions) support the full set of FASTGEN4 primitives. In the past, FASTGEN geometries had to be extruded into solid geometry primitives supported by BRL-CAD. Now, the primitives in FASTGEN are represented in BRL-CAD so there is no error introduced. FASTGEN files can now be seamlessly translated (point for point) into BRL-CAD.

 

Technical Questions

What platform is AJEM designed to run on?
 
Currently, AJEM is only compiled and tested to run on the following UNIX-based operating systems Red Hat Enterprise Linux (RHEL) 5 and CentOS Linux 5 for 64-bit with GCC 4.5.4.
 
Can I run AJEM on my PC?
 
If you want to run AJEM on a PC, you must first install a UNIX operating system (i.e., Linux).
 
What are AJEM's limitations?
 
As with any simulation, there are limitations which are based on the capability of the analyst and programmers to model real-world events, processor speed (which limits the level of fidelity in which an analysis may be performed), and funding levels for program development.
 
For a detailed answer to a specific question, review the Methodology section of the AJEM User/Analyst Manual and read about the methodology for which you have a question.
 
What does AJEM do that COVART does not?
 
The following tables identify some top-level comparisons:

 

Input File Comparisons

 Input Item

 COVART

 AJEM
Component Names

 8 Character Limit

 No Limit
Kill Levels

 Limit of 6

 No Limit
MV Group Items

Limit of 8 

 No Limit
Pk Tables per Component

 Limit of 4

 No Limit
Number of Pk Tables

 999

 No Limit
 
Capabilities Comparison

 Capability

 COVART

 AJEM
Integrated Encounter Module

No

 Yes
New Internal Blast & Combined Effects Methodologies

No

 Yes
Stochastic Analyses

No

 Yes
Built-In (i.e., _if(), _ifelse(), etc.) and User-Defined Functions in Fault Tree

No

 Yes
Fuel Tank Digitization & Leakage Algorithm

No 

 Yes
 
Built-In Utilities

 Input Item

 COVART

 AJEM
Graphical User Interface

No

Yes
On-Line Documentation

No

Yes
Built-In Vulnagram

No

Yes
Built-In Encounter Visualization

No

Yes