Web based evaluation of material handling alternatives for automated manufacturing : a parallel replications approach.

This research project describes the application of a master/slave configuration of processors to study a comparison of alternative material handling configurations for automated manufacturing. Such a study usually requires a large number of simulation replications, and carrying out those replications on a multi-processor platform can yield a significant savings in elapsed time. The objective of this study is to develop such a platform. In the present application, a parallel replication simulation system is developed to foster simultaneous processing. This system utilizes two separate applications to facilitate communication between master and slave computers. Additionally, the master and slave or client applications work in conjunction with a specialized set of Arena(tm) simulation models. The simulation models considered in this research effort represent two types of transport mechanisms in a closed cell work environment. Transport type, transport velocity, and an associated efficiency factor of a machine in cell 3. These models have been modified for use within the parallel replications environment. This system uses 2^3 = 8 design points (simulation models) for an experimental design. The models are transferred to remote PCUs via Transmission Control Protocol (TCP) file transfer. Following receipt, the models are executed, and results sent back to the master application where factor significance is determined. The resulting Metamodel (Kleijnen, 1979) describes a linear relationship between model variables, and system output

Evolutionary Synthesis of HVAC System Configurations: Algorithm Development.

This paper describes the development of an optimization procedure for the synthesis of novel heating, ventilating, and air-conditioning (HVAC) system configurations. Novel HVAC system designs can be synthesized using model-based optimization methods. The optimization problem can be considered as having three sub-optimization problems; the choice of a component set; the design of the topological connections between the components; and the design of a system operating strategy. In an attempt to limit the computational effort required to obtain a design solution, the approach adopted in this research is to solve all three sub-problems simultaneously. Further, the computational effort has been limited by implementing simplified component models and including the system performance evaluation as part of the optimization problem (there being no need in this respect to simulation the system performance). The optimization problem has been solved using a Genetic Algorithm (GA), with data structures and search operators that are specifically developed for the solution of HVAC system optimization problems (in some instances, certain of the novel operators may also be used in other topological optimization problems. The performance of the algorithm, and various search operators has been examined for a two-zone optimization problem (the objective of the optimization being to find a system design that minimizes the system energy use). In particular, the performance of the algorithm in finding feasible system designs has been examined. It was concluded that the search was unreliable when the component set was optimized, but if the component set was fixed as a boundary condition on the search, then the algorithm had an 81% probability of finding a feasible system design. The optimality of the solutions is not examined in this paper, but is described in an associated publication. It was concluded that, given a candidate set of system components, the algorithm described here provides an effective tool for exploring the novel design of HVAC systems. (c) HVAC & R journa

Quantifying the benefits of SPECint distant parallelism in simultaneous multithreading architectures

We exploit the existence of distant parallelism that future compilers could detect and characterise its performance under simultaneous multithreading architectures. By distant parallelism we mean parallelism that cannot be captured by the processor instruction window and that can produce threads suitable for parallel execution in a multithreaded processor. We show that distant parallelism can make feasible wider issue processors by providing more instructions from the distant threads, thus better exploiting the resources from the processor in the case of speeding up single integer applications. We also investigate the necessity of out-of-order processors in the presence of multiple threads of the same program. It is important to notice at this point that the benefits described are totally orthogonal to any other architectural techniques targeting a single thread.Peer ReviewedPostprint (published version