الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
The problem of computer network design is investigated in this dissertation. A linear 0-1 integer programming model is developed for the optimal design of distributed long-haul Point-to-point computer network. Compared with the previous work in this area. the model is more complete, since it considers simultaneously the following issues in designing computer networks:
1) Network Reliability
2) Database availability
3) Time Delay
4) Routing Strategy
5) Distribution of computing power
6) Allocation of programs and databases
7) Assignment of channels allocation and their capacities
8) Return flow of information
which includes the cost of users/programs to databases of information)
The obj ect i ve of the des ign process is achievement of the above design requirements at minimum cost. The following costs are considered by model:
1) Computers equipment cost
2) Database software cost
3) Channels installation cost which includes
a - Fixed cost depends on the channel capacity b - Variable cost depends on the channel length
4) Databases storage cost
5) programs storage cost
6) Usage cost of channels queries and• updates from (including the return flow
the the the
Several design problems had been overcomed:
1) No restriction is imposed on the topology of the designed network, and the network connectivity is optimally determined depending upon the nodes failure probabi I i ty and the requirement of the reI iabi li ty measure.
2) Depending on the node failure probability and the requirement of database availability measure, multiple copies of the same database are allocated at different sites in the network, and independent routes are assigned to access information at these copies.
3) The problem of dependencies between programs and databases is taken into account, thus, in order to access a database, the transaction has to be processed by a particular program related to that database.
4) The problem of return flow of information, as the response of a query transaction or the acknowledgment of an update transaction, is also considered by the model.
An algorithm based on the Balas algorithm for solving 0-1 LP problems has been developed to obtain the optimal solution of the model. The developed algorithm is more efficient than several existing general integer programming algorithms. Also, it avoids the disadvantages of heuristic and decomposition algorithms which are widely used in the optimization of computer networks and distributed databases. The algorithm is coded using both Microsoft FORTRAN version 5.1 and Turbo C++ and the
0-1 integer aspects of the
computation time of the program for several test problems is found less than that of other codes based on different algorithms and implemented using the same compiler.
The solution procedure is applied on an actual designed network to obtain the optimal design in the light of all the design issues mentioned before.
The two major contributions of this dissertation are:
1) Cons truct ing a more compl ete linear programming model that integrates most computer neworks design.
2) Modifying the Balas algorithm to be more efficient in solving 0-1 LP problems.