Characterisation of a reconfigurable free space optical interconnect system for parallel computing applications and experimental validation using rapid prototyping technology

Free-space optical interconnects (FSOIs) are widely seen as a potential solution to present and future bandwidth bottlenecks for parallel processing applications. This thesis will be focused on the study of a particular FSOI system called Optical Highway (OH). The OH is a polarised beam routing system which uses Polarising Beam Splitters and Liquid Crystals (PBS/LC) assemblies to perform reconfigurable interconnection networks. The properties of the OH make it suitable for implementing different passive static networks. A technology known as Rapid Prototyping (RP) will be employed for the first time in order to create optomechanical structures at low cost and low production times. Off-theshelf optical components will also be characterised in order to implement the OH. Additionally, properties such as reconfigurability, scalability, tolerance to misalignment and polarisation losses will be analysed. The OH will be modelled at three levels: node, optical stage and architecture. Different designs will be proposed and a particular architecture, Optimised Cut-Through Ring (OCTR), will be experimentally implemented. Finally, based on this architecture, a new set of properties will be defined in order to optimise the efficiency of the optical channels

Optimal cube-connected cube multiprocessors

Many CFD (computational fluid dynamics) and other scientific applications can be partitioned into subproblems. However, in general the partitioned subproblems are very large. They demand high performance computing power themselves, and the solutions of the subproblems have to be combined at each time step. The cube-connect cube (CCCube) architecture is studied. The CCCube architecture is an extended hypercube structure with each node represented as a cube. It requires fewer physical links between nodes than the hypercube, and provides the same communication support as the hypercube does on many applications. The reduced physical links can be used to enhance the bandwidth of the remaining links and, therefore, enhance the overall performance. The concept and the method to obtain optimal CCCubes, which are the CCCubes with a minimum number of links under a given total number of nodes, are proposed. The superiority of optimal CCCubes over standard hypercubes was also shown in terms of the link usage in the embedding of a binomial tree. A useful computation structure based on a semi-binomial tree for divide-and-conquer type of parallel algorithms was identified. It was shown that this structure can be implemented in optimal CCCubes without performance degradation compared with regular hypercubes. The result presented should provide a useful approach to design of scientific parallel computers

Processor allocation strategies for modified hypercubes

Parallel processing has been widely accepted to be the future in high speed computing. Among the various parallel architectures proposed/implemented, the hypercube has shown a lot of promise because of its poweful properties, like regular topology, fault tolerance, low diameter, simple routing, and ability to efficiently emulate other architectures. The major drawback of the hypercube network is that it can not be expanded in practice because the number of communication ports for each processor grows as the logarithm of the total number of processors in the system. Therefore, once a hypercube supercomputer of a certain dimensionality has been built, any future expansions can be accomplished only by replacing the VLSI chips. This is an undesirable feature and a lot of work has been under progress to eliminate this stymie, thus providing a platform for easier expansion. Modified hypercubes (MHs) have been proposed as the building blocks of hypercube-based systems supporting incremental growth techniques without introducing extra resources for individual hypercubes. However, processor allocation on MHs proves to be a challenge due to a slight deviation in their topology from that of the standard hypercube network. This thesis addresses the issue of processor allocation on MHs and proposes various strategies which are based, partially or entirely, on table look-up approaches. A study of the various task allocation strategies for standard hypercubes is conducted and their suitability for MHs is evaluated. It is shown that the proposed strategies have a perfect subcube recognition ability and a superior performance. Existing processor allocation strategies for pure hypercube networks are demonstrated to be ineffective for MHs, in the light of their inability to recognize all available subcubes. A comparative analysis that involves the buddy strategy and the new strategies is carried out using simulation results

Parallel scanning of implicit surfaces with the simplex algorithm

Solution of mechanical problems often requires the analytical or numerical calculation of equilibrium paths, while solution sets of other dimension than one are rare. From this requirement emerged numerous method for the calculation of bifurcation diagrams. Two large group of the solution methods are the continuation methods and the scanning methods (however hybrid algorithm exists as well). The Simplex Algorithm is a robust approximative technique based on the Piecewise Linearization (PL-)algorithm, which has its application as a continuation and as a scanning algorithm as well. In this paper we will show the extension of the method for finding a 2-dimensional manifold (i.e. surface) with the scanning of the parameter space. We analyze the performance of the algorithm and its parallelization through two simple examples

ExCCC-DCN: A Highly Scalable, Cost-Effective and Engergy-Efficient Data Center Stucture

PublishedThis is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Over the past decade, many data centers have been constructed around the world due to the explosive growth of data volume and type. The cost and energy consumption have become the most important challenges of building those data centers. Data centers today use commodity computers and switches instead of high-end servers and interconnections for cost-effectiveness. In this paper, we propose a new type of interconnection networks called Exchanged Cube-Connected Cycles (ExCCC). The ExCCC network is an extension of Exchanged Hypercube (EH) network by replacing each node with a cycle. The EH network is based on link removal from a Hypercube network, which makes the EH network more cost-effective as it scales up. After analyzing the topological properties of ExCCC, we employ commodity switches to construct a new class of data center network models, namely ExCCC-DCN, by leveraging the advantages of the ExCCC architecture. The analysis and experimental results demonstrate that the proposed ExCCC-DCN models significantly outperform four state-of-the-art data center network models in terms of the total cost, power consumption, scalability, and other static characteristics. It achieves the goals of low cost, low energy consumption, high network throughput, and high scalability simultaneously.This work is supported by the National Natural Science Foundation (NSF) of China under Grant (No. 61572232, and No. 61272073), the key program of Natural Science Foundation of Guangdong Province (No.S2013020012865), and the Fundamental Research Funds for the Central Universities

Alternately-twisted cube as an interconnection network.

by Wong Yiu Chung.Thesis (M.Phil.)--Chinese University of Hong Kong, 1991.Bibliography: leaves [100]-[101]AcknowledgementAbstractChapter 1. --- Introduction --- p.1-1Chapter 2. --- Alternately-Twisted Cube: Definition & Graph-Theoretic Properties --- p.2-1Chapter 2.1. --- Construction --- p.2-1Chapter 2.2. --- Topological Properties --- p.2-12Chapter 2.2.1. --- "Node Degree, Link Count & Diameter" --- p.2-12Chapter 2.2.2. --- Node Symmetry --- p.2-13Chapter 2.2.3. --- Sub cube Partitioning --- p.2-18Chapter 2.2.4. --- Distinct Paths --- p.2-23Chapter 2.2.5. --- Embedding other networks --- p.2-24Chapter 2.2.5.1. --- Rings --- p.2-25Chapter 2.2.5.2. --- Grids --- p.2-29Chapter 2.2.5.3. --- Binary Trees --- p.2-35Chapter 2.2.5.4. --- Hypercubes --- p.2-42Chapter 2.2.6. --- Summary of Comparison with the Hypercube --- p.2-44Chapter 3. --- Network Properties --- p.3-1Chapter 3.1. --- Routing Algorithms --- p.3-1Chapter 3.2. --- Message Transmission: Static Analysis --- p.3-5Chapter 3.3. --- Message Transmission: Dynamic Analysis --- p.3-13Chapter 3.4. --- Broadcasting --- p.3-17Chapter 4. --- Parallel Processing on the Alternately-Twisted Cube --- p.4-1Chapter 4.1. --- Ascend/Descend class algorithms --- p.4-1Chapter 4.2. --- Combining class algorithms --- p.4-7Chapter 4.3. --- Numerical algorithms --- p.4-8Chapter 5. --- "Summary, Comparison & Conclusion" --- p.5-1Chapter 5.1. --- Summary --- p.5-1Chapter 5.2. --- Comparison with other hypercube-like networks --- p.5-2Chapter 5.3. --- Conclusion --- p.5-7Chapter 5.4. --- Possible future research --- p.5-7Bibliograph