Adaptive and secured resource management in distributed and Internet systems

The effectiveness of computer system resource management has been always determined by two major factors: (1) workload demands and management objectives, (2) the updates of the computer technology. These two factors are dynamically changing, and resource management systems must be timely adaptive to the changes. This dissertation attempts to address several important and related resource management issues.;We first study memory system utilization in centralized servers by improving memory performance of sorting algorithms, which provides fundamental understanding on memory system organizations and its performance optimizations for data-intensive workloads. to reduce different types of cache misses, we restructure the mergesort and quicksort algorithms by integrating tiling, padding, and buffering techniques and by repartitioning the data set. Our study shows substantial performance improvements from our new methods.;We have further extended the work to improve load sharing for utilizing global memory resources in distributed systems. Aiming at reducing the memory resource contention caused by page faults and I/O activities, we have developed and examined load sharing policies by considering effective usage of global memory in addition to CPU load balancing in both homogeneous and heterogeneous clusters.;Extending our research from clusters to Internet systems, we have further investigated memory and storage utilizations in Web caching systems. We have proposed several novel management schemes to restructure and decentralize the existing caching system by exploiting data locality at different levels of the global memory hierarchy and by effectively sharing data objects among the clients and their proxy caches.;Data integrity and communication anonymity issues are raised from our decentralized Web caching system design, which are also security concerns for general peer-to-peer systems. We propose an integrity protocol to ensure data integrity, and several protocols to achieve mutual communication anonymity between an information requester and a provider.;The potential impact and contributions of this dissertation are briefly stated as follows: (1) two major research topics identified in this dissertation are fundamentally important for the growth and development of information technology, and will continue to be demanding topics for a long term. (2) Our proposed cache-effective sorting methods bridge a serious gap between analytical complexity of algorithms and their execution complexity in practice due to the increasingly deep memory hierarchy in computer systems. This approach can also be used to improve memory performance at different levels of the memory hierarchy, such as I/O and file systems. (3) Our load sharing principle of giving a high priority to the requests of data accesses in memory and I/Os timely adapts the technology changes and effectively responds to the increasing demand of data-intensive applications. (4) Our proposed decentralized Web caching framework and its resource management schemes present a comprehensive case study to examine the P2P model. Our results and experiences can be used for related and further studies in distributed computing. (5) The proposed data integrity and communication anonymity protocols address limits and weaknesses of existing ones, and place a solid foundation for us to continue our work in this important area

Cache based optimization of stencil computations : an algorithmic approach

We are witnessing a fundamental paradigm shift in computer design. Memory has been and is becoming more hierarchical. Clock frequency is no longer crucial for performance. The on-chip core count is doubling rapidly. The quest for performance is growing. These facts have lead to complex computer systems which bestow high demands on scientific computing problems to achieve high performance. Stencil computation is a frequent and important kernel that is affected by this complexity. Its importance stems from the wide variety of scientific and engineering applications that use it. The stencil kernel is a nearest-neighbor computation with low arithmetic intensity, thus it usually achieves only a tiny fraction of the peak performance when executed on modern computer systems. Fast on-chip memory modules were introduced as the hardware approach to alleviate the problem. There are mainly three approaches to address the problem, cache aware, cache oblivious, and automatic loop transformation approaches. In this thesis, comprehensive cache aware and cache oblivious algorithms to optimize stencil computations on structured rectangular 2D and 3D grids are presented. Our algorithms observe the challenges for high performance in the previous approaches, devise solutions for them, and carefully balance the solution building blocks against each other. The many-core systems put the scalability of memory access at stake which has lead to hierarchical main memory systems. This adds another locality challenge for performance. We tailor our frameworks to meet the new performance challenge on these architectures. Experiments are performed to evaluate the performance of our frameworks on synthetic as well as real world problems.Wir erleben gerade einen fundamentalen Paradigmenwechsel im Computer Design. Speicher wird immer mehr hierarchisch gegliedert. Die CPU Frequenz ist nicht mehr allein entscheidend für die Rechenleistung. Die Zahl der Kerne auf einem Chip verdoppelt sich in kurzen Zeitabständen. Das Verlangen nach mehr Leistung wächst dabei ungebremst. Dies hat komplexe Computersysteme zur Folge, die mit schwierigen Problemen aus dem Bereich des wissenschaftlichen Rechnens einhergehen um eine hohe Leistung zu erreichen. Stencil Computation ist ein häufig eingesetzer und wichtiger Kernel, der durch diese Komplexität beeinflusst ist. Seine Bedeutung rührt von dessen zahlreichen wissenschaftlichen und ingenieurstechnischen Anwendungen. Der Stencil Kernel ist eine Nächster-Nachbar-Berechnung von niedriger arithmetischer Intensität. Deswegen erreicht es nur einen Bruchteil der möglichen Höchstleistung, wenn es auf modernen Computersystemen ausgeführt wird. Es gibt im Wesentlichen drei Möglichkeiten dieses Problem anzugehen, und zwar durch cache-bewusste, cache-unbewusste und automatische Schleifentransformationsansätze. In dieser Doktorarbeit stellen wir vollständige cache-bewusste sowie cache-unbewusste Algorithmen zur Optimierung von Stencilberechnungen auf einem strukturierten rechteckigen 2D und 3D Gitter. Unsere Algorithmen erfüllen die Erfordernisse für eine hohe Leistung und wiegen diese sorgfältig gegeneinander ab. Das Problem der Skalierbarkeit von Speicherzugriffen führte zu hierarchischen Speichersystemen. Dies stellt eine weitere Herausforderung an die Leistung dar. Wir passen unser Framework dahingehend an, um mit dieser Herausforderung auf solchen Architekturen fertig zu werden. Wir führen Experimente durch, um die Leistung unseres Algorithmen auf synthetischen wie auch realen Problemen zu evaluieren

Fourth Conference on Artificial Intelligence for Space Applications

Proceedings of a conference held in Huntsville, Alabama, on November 15-16, 1988. The Fourth Conference on Artificial Intelligence for Space Applications brings together diverse technical and scientific work in order to help those who employ AI methods in space applications to identify common goals and to address issues of general interest in the AI community. Topics include the following: space applications of expert systems in fault diagnostics, in telemetry monitoring and data collection, in design and systems integration; and in planning and scheduling; knowledge representation, capture, verification, and management; robotics and vision; adaptive learning; and automatic programming

Graphics Technology in Space Applications (GTSA 1989)

This document represents the proceedings of the Graphics Technology in Space Applications, which was held at NASA Lyndon B. Johnson Space Center on April 12 to 14, 1989 in Houston, Texas. The papers included in these proceedings were published in general as received from the authors with minimum modifications and editing. Information contained in the individual papers is not to be construed as being officially endorsed by NASA

Interactive Video Game Content Authoring using Procedural Methods

This thesis explores avenues for improving the quality and detail of game graphics, in the context of constraints that are common to most game development studios. The research begins by identifying two dominant constraints; limitations in the capacity of target gaming hardware/platforms, and processes that hinder the productivity of game art/content creation. From these constraints, themes were derived which directed the research‟s focus. These include the use of algorithmic or „procedural‟ methods in the creation of graphics content for games, and the use of an „interactive‟ content creation strategy, to better facilitate artist production workflow. Interactive workflow represents an emerging paradigm shift in content creation processes used by the industry, which directly integrates game rendering technology into the content authoring process. The primary motivation for this is to provide „high frequency‟ visual feedback that enables artists to see games content in context, during the authoring process. By merging these themes, this research develops a production strategy that takes advantage of „high frequency feedback‟ in an interactive workflow, to directly expose procedural methods to artists‟, for use in the content creation process. Procedural methods have a characteristically small „memory footprint‟ and are capable of generating massive volumes of data. Their small „size to data volume‟ ratio makes them particularly well suited for use in game rendering situations, where capacity constraints are an issue. In addition, an interactive authoring environment is well suited to the task of setting parameters for procedural methods, reducing a major barrier to their acceptance by artists. An interactive content authoring environment was developed during this research. Two algorithms were designed and implemented. These algorithms provide artists‟ with abstract mechanisms which accelerate common game content development processes; namely object placement in game environments, and the delivery of variation between similar game objects. In keeping with the theme of this research, the core functionality of these algorithms is delivered via procedural methods. Through this, production overhead that is associated with these content development processes is essentially offloaded from artists onto the processing capability of modern gaming hardware. This research shows how procedurally based content authoring algorithms not only harmonize with the issues of hardware capacity constraints, but also make the authoring of larger and more detailed volumes of games content more feasible in the game production process. Algorithms and ideas developed during this research demonstrate the use of procedurally based, interactive content creation, towards improving detail and complexity in the graphics of games

The Sixth Annual Workshop on Space Operations Applications and Research (SOAR 1992)

This document contains papers presented at the Space Operations, Applications, and Research Symposium (SOAR) hosted by the U.S. Air Force (USAF) on 4-6 Aug. 1992 and held at the JSC Gilruth Recreation Center. The symposium was cosponsored by the Air Force Material Command and by NASA/JSC. Key technical areas covered during the symposium were robotic and telepresence, automation and intelligent systems, human factors, life sciences, and space maintenance and servicing. The SOAR differed from most other conferences in that it was concerned with Government-sponsored research and development relevant to aerospace operations. The symposium's proceedings include papers covering various disciplines presented by experts from NASA, the USAF, universities, and industry

An efficient virtual network interface in the FUGU scalable workstation dc by Kenneth Martin Mackenzie.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 123-129).Ph.D

The 1991 3rd NASA Symposium on VLSI Design

Papers from the symposium are presented from the following sessions: (1) featured presentations 1; (2) very large scale integration (VLSI) circuit design; (3) VLSI architecture 1; (4) featured presentations 2; (5) neural networks; (6) VLSI architectures 2; (7) featured presentations 3; (8) verification 1; (9) analog design; (10) verification 2; (11) design innovations 1; (12) asynchronous design; and (13) design innovations 2

Research and technology, 1992

Selected research and technology activities at Ames Research Center, including the Moffett Field site and the Dryden Flight Research Facility, are summarized. These activities exemplify the Center's varied and productive research efforts for 1992