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Full-Text Articles in Physical Sciences and Mathematics
Structural Model Checking, Radu Siminiceanu
Structural Model Checking, Radu Siminiceanu
Dissertations, Theses, and Masters Projects
The introduction of symbolic approaches, based on Binary Decision Diagrams (BDD), to Model Checking has led to significant improvements in Formal Verification, by allowing the analysis of very large systems, such as complex circuit designs. These were previously beyond the reach of traditional, explicit methods, due to the state space explosion phenomenon. However, after the initial success, the BDD technology has peaked, due to a similar problem, the BDD explosion.;We present a new approach to symbolic Model Checking that is based on exploiting the system structure. This technique is characterized by several unique features, including an encoding of states with …
Optimizing Combat Capabilities By Modeling Combat As A Complex Adaptive System, Steven Mains
Optimizing Combat Capabilities By Modeling Combat As A Complex Adaptive System, Steven Mains
Dissertations, Theses, and Masters Projects
Procuring combat systems in the Department of Defense is a balancing act where many variables, only some under control of the department, shift simultaneously. Technology changes non-linearly, providing new opportunities and new challenges to the existing and potential force. Money available changes year over year to fit into the overall US Government budget. Numbers of employees change through political demands rather than by cost-effectiveness considerations. The intent is to provide the best mix of equipment to field the best force against an expected enemy while maintaining adequate capability against the unexpected. Confounding this desire is the inability of current simulations …
Files As First-Class Objects In Fault -Tolerant Concurrent Systems, Robert Edwin Matthews
Files As First-Class Objects In Fault -Tolerant Concurrent Systems, Robert Edwin Matthews
Dissertations, Theses, and Masters Projects
Concurrent systems are used in applications where multiple processors are needed to complete tasks within a reasonable amount of time, or where the data sets involved will not fit within the main memory of a single computer. Because of their reliance on multiple machines, such systems are proportionally more vulnerable to both hardware and software induced failures. Fault-tolerance schemes are used to recover some earlier consistent state of the system after such a failure.;One important technique used to achieve fault-tolerance is checkpointing and rollback-recovery. In this thesis, we present a method for efficiently and transparently incorporating the part of the …
Runtime Support For Load Balancing Of Parallel Adaptive And Irregular Applications, Kevin James Barker
Runtime Support For Load Balancing Of Parallel Adaptive And Irregular Applications, Kevin James Barker
Dissertations, Theses, and Masters Projects
Applications critical to today's engineering research often must make use of the increased memory and processing power of a parallel machine. While advances in architecture design are leading to more and more powerful parallel systems, the software tools needed to realize their full potential are in a much less advanced state. In particular, efficient, robust, and high-performance runtime support software is critical in the area of dynamic load balancing. While the load balancing of loosely synchronous codes, such as field solvers, has been studied extensively for the past 15 years, there exists a class of problems, known as asynchronous and …
Building Internet Caching Systems For Streaming Media Delivery, Songqing Chen
Building Internet Caching Systems For Streaming Media Delivery, Songqing Chen
Dissertations, Theses, and Masters Projects
The proxy has been widely and successfully used to cache the static Web objects fetched by a client so that the subsequent clients requesting the same Web objects can be served directly from the proxy instead of other sources faraway, thus reducing the server's load, the network traffic and the client response time. However, with the dramatic increase of streaming media objects emerging on the Internet, the existing proxy cannot efficiently deliver them due to their large sizes and client real time requirements.;In this dissertation, we design, implement, and evaluate cost-effective and high performance proxy-based Internet caching systems for streaming …
Efficient Caching Algorithms For Memory Management In Computer Systems, Song Jiang
Efficient Caching Algorithms For Memory Management In Computer Systems, Song Jiang
Dissertations, Theses, and Masters Projects
As disk performance continues to lag behind that of memory systems and processors, fully utilizing memory to reduce disk accesses is a highly effective effort to improve the entire system performance. Furthermore, to serve the applications running on a computer in distributed systems, not only the local memory but also the memory on remote servers must be effectively managed to minimize I/O operations. The critical challenges in an effective memory cache management include: (1) Insightfully understanding and quantifying the locality inherent in the memory access requests; (2) Effectively utilizing the locality information in replacement algorithms; (3) Intelligently placing and replacing …
Lookahead Scheduling In A Real-Time Context: Models, Algorithms, And Analysis, Benjamin J. Coleman
Lookahead Scheduling In A Real-Time Context: Models, Algorithms, And Analysis, Benjamin J. Coleman
Dissertations, Theses, and Masters Projects
Our research considers job scheduling, a special type of resource assignment problem. For example, at a cross-docking facility trucks must be assigned to doors where they will be unloaded. The cargo on each truck has various destinations within the facility, and the unloading time for a truck is dependent on the distance from the assigned door to these destinations. The goal is to assign the trucks to doors while minimizing the amount of time to unload all trucks.;We study scheduling algorithms for problems like the cross-docking example that are different from traditional algorithms in two ways. First, we utilize real-time, …
Dynamic Adaptation To Cpu And Memory Load In Scientific Applications, Richard Tran Mills
Dynamic Adaptation To Cpu And Memory Load In Scientific Applications, Richard Tran Mills
Dissertations, Theses, and Masters Projects
As commodity computers and networking technologies have become faster and more affordable, fairly capable machines have become nearly ubiquitous while the effective "distance" between them has decreased as network connectivity and capacity has multiplied. There is considerable interest in developing means to readily access such vast amounts of computing power to solve scientific problems, but the complexity of these modern computing environments pose problems for conventional computer codes designed to run on a static, homogeneous set of resources. One source of problems is the heterogeneity that is naturally present in these settings. More problematic is the competition that arises between …