PHYSICAL FUNCTIONS COST FUNCTIONS 
PHASES Equip- |Mainte- | Adminis- Total 
Modules ment nance tration 
  
  
  
   
    
    
    
    
   
    
     
  
#1 
#2 
Information : 
m 
Total :Information = S s Ss 
#1 
#2 
il 
re 
  
Speculation 
m 
Total:Speculation = = = => 2 
#1 
#2 
Il 
un 
  
Analysis 
m 
Total: Analyses = = = ZZ = A 
#1 
#2 
  
Execution, 
Application m 
Total:Application = = S =2 à = E 
  
  
  
  
  
All Total System Cost I+S+A+E 
  
  
  
    
Figure 5 : System Cost Matrix 
  
   
     
    
    
   
    
    
   
  
   
   
    
    
time for that job). 
3. Reliability (R) , for the whole system may be defined as the pro- 
bability that the system will perform as expected for the duration of its 
mission. It should not be confused with Availability. It may be express- 
ed as follows 
R = e~t/T 
  
  
  
base of natural logarithm 
duration of an operation or mission 
mean time between failures 
where e 
t 
T 
  
il 
4. Survivability (S) : The expected survivability can be seen from 
the point of view of threat of technological obsolescence, in whole or 
in part. 
Effectiveness-model 
  
Considering the four effectiveness factors, an expression for the sys- 
tems effectiveness is evolved based on the product of the expectations 
(P,A,R,S) giving the resultant expectations of the system's effectiveness 
(analogous to product of probabilities): 
E = [PC5] [AC4] [RC] 1 [805] 
  
  
where the C's are the respective index- 
es of statistical confidences. In a simplified concept, an effective- 
ness-model could represent an interaction between the basic design and 
the realized design. The former (basic design) is a parametric descrip- 
tion of a new system as it would operate in the absence of any adverse