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Thermodynamic Cycle Analysis Program (TCAP)

Description: This report describes the Thermodynamic Cycle Analysis Program (TCAP) software developed in support of the Collaborative Advanced Gas Turbine (CAGT) research project. The goal of the CAGT project was to evaluate different configurations of gas turbine-based power generation cycles. TCAP software enables the user to graphically construct power cycles that incorporate a variety of components such as compressors, turbines, heat exchangers, and reactors. The user also specifies the input condition of the working fluid and the parameters associated with each component. TCAP then calculates the composition and thermodynamic properties of the working fluid at every point in the cycle. From this data, TCAP calculates the overall thermodynamic efficiency of the cycle and emission levels of specific chemicals. Thermodynamic and chemical kinetic data are based on the Chemkin family of application codes and libraries.
Date: January 1, 1997
Creator: Yoshimura, A.S.
Partner: UNT Libraries Government Documents Department

Infrastructure for distributed enterprise simulation

Description: Traditional discrete-event simulations employ an inherently sequential algorithm and are run on a single computer. However, the demands of many real-world problems exceed the capabilities of sequential simulation systems. Often the capacity of a computer`s primary memory limits the size of the models that can be handled, and in some cases parallel execution on multiple processors could significantly reduce the simulation time. This paper describes the development of an Infrastructure for Distributed Enterprise Simulation (IDES) - a large-scale portable parallel simulation framework developed to support Sandia National Laboratories` mission in stockpile stewardship. IDES is based on the Breathing-Time-Buckets synchronization protocol, and maps a message-based model of distributed computing onto an object-oriented programming model. IDES is portable across heterogeneous computing architectures, including single-processor systems, networks of workstations and multi-processor computers with shared or distributed memory. The system provides a simple and sufficient application programming interface that can be used by scientists to quickly model large-scale, complex enterprise systems. In the background and without involving the user, IDES is capable of making dynamic use of idle processing power available throughout the enterprise network. 16 refs., 14 figs.
Date: January 1, 1998
Creator: Johnson, M.M.; Yoshimura, A.S. & Goldsby, M.E.
Partner: UNT Libraries Government Documents Department

The IDES framework: A case study in development of a parallel discrete-event simulation system

Description: This tutorial describes considerations in the design and development of the IDES parallel simulation system. IDES is a Java-based parallel/distributed simulation system designed to support the study of complex large-scale enterprise systems. Using the IDES system as an example, the authors discuss how anticipated model and system constraints molded the design decisions with respect to modeling, synchronization, and communication strategies.
Date: December 31, 1997
Creator: Nicol, D.M.; Johnson, M.M. & Yoshimura, A.S.
Partner: UNT Libraries Government Documents Department

A system simulation to enhance stockpile stewardship (ASSESS)

Description: This paper describes the ASSESS project, whose goal is to construct a policy driven enterprise simulation of the DOE nuclear weapons complex (DOE/NWC). ASSESS encompasses the full range of stockpile stewardship activities by incorporating simulation component models that are developed and managed by local experts. ASSESS runs on a heterogeneous distributed computing environment and implements multi-layered user access capabilities. ASSESS allows the user to create hypothetical policies governing stockpile stewardship, simulate the resulting operation of the DOE/NWC, and analyze the relative impact of each policy.
Date: November 1, 1997
Creator: Yoshimura, A.S.; Plantenga, T.D.; Napolitano, L.M. & Johnson, M.M.
Partner: UNT Libraries Government Documents Department

Large-Scale Information Systems

Description: Large enterprises are ever more dependent on their Large-Scale Information Systems (LSLS), computer systems that are distinguished architecturally by distributed components--data sources, networks, computing engines, simulations, human-in-the-loop control and remote access stations. These systems provide such capabilities as workflow, data fusion and distributed database access. The Nuclear Weapons Complex (NWC) contains many examples of LSIS components, a fact that motivates this research. However, most LSIS in use grew up from collections of separate subsystems that were not designed to be components of an integrated system. For this reason, they are often difficult to analyze and control. The problem is made more difficult by the size of a typical system, its diversity of information sources, and the institutional complexities associated with its geographic distribution across the enterprise. Moreover, there is no integrated approach for analyzing or managing such systems. Indeed, integrated development of LSIS is an active area of academic research. This work developed such an approach by simulating the various components of the LSIS and allowing the simulated components to interact with real LSIS subsystems. This research demonstrated two benefits. First, applying it to a particular LSIS provided a thorough understanding of the interfaces between the system's components. Second, it demonstrated how more rapid and detailed answers could be obtained to questions significant to the enterprise by interacting with the relevant LSIS subsystems through simulated components designed with those questions in mind. In a final, added phase of the project, investigations were made on extending this research to wireless communication networks in support of telemetry applications.
Date: December 1, 2000
Creator: Nicol, D. M.; Ammerlahn, H. R.; Goldsby, M. E.; Johnson, M. M.; Rhodes, D. E. & Yoshimura, A. S.
Partner: UNT Libraries Government Documents Department