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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Strategic valve locations in a water distribution system

Jun, Hwandon 22 June 2005 (has links)
Valves play a critical role in a water distribution system for subsystem isolation and flow or pressure control. Among them, subsystem isolation is required to repair or to rehabilitate a broken component and can be done by closing adjacent valves. To evaluate the role of valves, the concept of "Segment" is necessary. A segment consists of a set of pipes and nodes isolated together by closing adjacent valves when a pipe fails. An efficient algorithm to identify segments in a water distribution system is proposed. In addition, when a segment is isolated, an additional subsystem may be disconnected from water sources by the segment isolation. It is a topological unintended isolation. In addition, a hydraulic failure, in terms of pressure types of failures at demand nodes should be considered. These three account for the failure impact of a pipe. Placing valves efficiently improves the reliability of a water distribution system. However, the valve reliability itself is not 100%. Therefore, valve failure consequence should be explored in determining the locations of valves. For this purpose, three methodologies, namely segment-valve matrix algorithm, decision tree approach and simulation are proposed. Another consideration for placing valves is a strategic valving rule, namely N and (N-1) valving rules. Using a formulation for node reliability in terms of failing valves, the reliability difference between the two valving rules is evaluated. We also employ a mixed N and (N-1) valving rule. Another strategic valving rule, a segment size reducing approach minimizing the number of affected customers is proposed. The developed algorithms are utilized to build software, the Strategic Valve Management Model, to solve practical problems. The methodology is applied to three real water distribution systems. / Ph. D.
2

Speeding up matrix computation kernels by sharing vector coprocessor among multiple cores on chip

Dahlberg, Christopher January 2012 (has links)
Today’s computer systems develop towards less energy consumption while keeping high performance. These are contradictory requirement and pose a great challenge. A good example of an application were this is used is the smartphone. The constraints are on long battery time while getting high performance required by future 2D/3D applications. A solution to this is heterogeneous systems that have components that are specialized in different tasks and can execute them fast with low energy consumption. These could be specialized i.e. encoding/decoding, encryption/decryption, image processing or communication. At the apartment of Computer Architecture and Parallel Processing Laboratory (CAPPL) at New Jersey Institute of Technology (NJIT) a vector co-processor has been developed. The Vector co-processor has the unusual feature of being able to receive instructions from multiple hosts (scalar cores). In addition to this a test system with a couple of scalar processors using the vector processor has been developed. This thesis describes this processor and its test system. It also shows the development of math applications involving matrix operations. This results in the conclusions of the vector co-processing saving substantial amount of energy while speeding up the execution of the applications. In addition to this the thesis will describe an extension of the vector co-processor design that makes it possible to monitor the throughput of instructions and data in the processor.

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