Computer programs

The objective of the work is to verify the feasibility of converting a large FEA code into a massively parallel FEA code in terms of computational speed and cost. Sequential subroutines in the Research EPIC hydro code, a Lagrangian finite element analysis code for high velocity elastic-plastic impact problems, are individually converted into parallel code using Cray Adaptive Fortran (CRAFT). The performance of massively parallel subroutines running on 32 PEs on Cray-T3D is faster than their sequential counterparts on Cray-YMP. At next stage of the research, Parallel Virtual Machine (PVM) directives is used to develop a PVM version of the EPIC hydro code by connecting the converted parallel subroutines running on multiple PEs of T3D to the sequential part of the code running on single PE. With an incremental increase in the massively parallel subroutines into the PVM EPIC hydro code, the performance with respect to speedup of the code increased accordingly. The results indicate that significant speedup can be achieved in the EPIC hydro code when most or all of the subroutines are massively parallelized.

A new approach has been developed for inverse kinematic analysis of redundant robots. In case of redundant robots inverse kinematics is complicated by the non-square nature of the Jacobian. In this method the Jacobian and inverse kinematic equation are reduced based on the rank of the Jacobian and the constraints specified. This process automatically locks some joints of the robot at various trajectory points. The reduced inverse kinematic equation is solved by an iterative procedure to find joint variable values for known task description. The results of computer simulation of the inverse kinematics applied on a redundant planar robot and a redundant moving base robot proved the method to be efficient, and the results can be found within a few iterations with excellent accuracy.

Through a small contained environment, this study evaluates an information-based complexity metric theory and its relationship to the effort expended in constructing a program. The metric, which calculates the amount of information present in a program specification, determines the specification's complexity measure. The observed measures of programmer effort were the numbers of keystrokes, insertions, deletions, and runs needed to complete the program specification. It was theorized that a program with a higher complexity value than that of another program will require more programmer resources to complete. A significant relationship between the metric and the number of keystrokes was found.

Web Service Business Process Execution Language (BPEL) has become a standard language in the world of Service Oriented Architecture (SOA) for specifying interactions between internet services. This standard frees developers from low-level concerns involving platform, implementation, and versioning. These freedoms risk development of less robust artifacts that may even become part of a mission-critical system. Model checking a BPEL artifact for correctness with respect to temporal logic properties is computationally complex, since it requires enumerating all communication and synchronization amongst various services with itself. This entails modeling BPEL features such as concurrency, hierarchy, interleaving, and non-deterministic choice. The thesis will provide rules and procedures for translating these features to a veriable model written in Promela. We will use these rules to build a program which automates the translation process, bringing us one step closer to push button verification. Finally, two BPEL artifacts will be translated, manually edited, verified, and analyzed.

This thesis is an approach of numerical optimization of thermal design of the ocean turbine developed by the Centre of Ocean Energy and Technology (COET). The technique used here is the integrated method of finite element analysis (FEA) of heat transfer, artificial neural network (ANN) and genetic algorithm (GA) for optimization purposes.

Reliability is a key system characteristic that is an increasing concern for current systems. Greater reliability is necessary due to the new ways in which services are delivered to the public. Services are used by many industries, including health care, government, telecommunications, tools, and products. We have defined an approach to incorporate reliability along the stages of system development. We first did a survey of existing dependability patterns to evaluate their possible use in this methodology. We have defined a systematic methodology that helps the designer apply reliability in all steps of the development life cycle in the form of patterns. A systematic failure enumeration process to define corresponding countermeasures was proposed as a guideline to define where reliability is needed. We introduced the idea of failure patterns which show how failures manifest and propagate in a system. We also looked at how to combine reliability and security. Finally, we defined an approach to certify the level of reliability of an implemented web service. All these steps lead towards a complete methodology.

In recent years, there has been an exponential increase in container volume shipment within intermodal transportation systems. Container terminals as part of the global port system represent important hubs within this intermodal transportation system. Thus, the need to improve the operational efficiency is the most important issue for container terminals from an economic standpoint. Moreover, intermodal transportation systems, ports and inland transport facilities should all be integrated into one coordinated plan. More specifically, a method to schedule different types of handling equipment in an integrated way within a container terminal is a popular topic for researchers. However, not many researchers have addresses this topic in relationship to the simulation aspect which will test feasible solutions under real container terminal environment parameters. In order to increase the efficiency of operations, the development of mathematical models and algorithms is critical in finding the best feasible solution. The objective of this study is to evaluate the feasible solution to find the proper number of Yard Trailers (YTs) with the minimal cost for the container terminals. This study uses the Dynamic YTs operation's method as a background for modeling. A mathematical model with various constraints related to the integrated operations among the different types of handling equipment is formulated. This model takes into consideration both serving time of quay cranes and yard cranes, and cost reduction strategies by decreasing use of YTs with the specific objective of minimum total cost including utilization of YTs and vessel berthing. In addition, a heuristic algorithm combined with Monte Carlo Method and Brute-Force Search are employed. The early Stage Technique of Monte Carlo method is proposed to generate vast random numbers to replicate simulation for real cases.

Web services intend to provide an application integration technology that can be successfully used over the Internet in a secure, interoperable and trusted manner. Policies are high-level guidelines defining the way an institution conducts its activities. The WS-Policy standard describes how to apply policies of security definition, enforcement of access control, authentication and logging. WS-Trust defines a security token service and a trust engine which are used by web services to authenticate other web services. Using the functions defined in WS-Trust, applications can engage in secure communication after establishing trust. BPEL is a language for web service composition that intends to provide convenient and effective means for application integration over the Internet. We address security considerations in BPEL and how to enforce them, as well as its interactions with other web services standards such as WS-Security and WS-Policy.

The need to achieve dependability in critical infrastructures has become indispensable for government and commercial enterprises. This need has become more necessary with the proliferation of malicious attacks on critical systems, such as healthcare, aerospace and airline applications. Additionally, due to the widespread use of web services in critical systems, the need to ensure their reliability is paramount. We believe that patterns can be used to achieve dependability. We conducted a survey of fault tolerance, reliability and web service products and patterns to better understand them. One objective of our survey is to evaluate the state of these patterns, and to investigate which standards are being used in products and their tool support. Our survey found that these patterns are insufficient, and many web services products do not use them. In light of this, we wrote some fault tolerance and web services reliability patterns and present an analysis of them.