Managing Change in Information Systems : technological challenges

Information systems and other computer-based systems must continuously undergo change in order to reflect change in their environments. The present technology used to implement such systems, including models, methods, tools and languages, does not have an inherent understanding of the nature of evolution. The rigidity of existing systems is a hindrance for user requested enhancements.Propagating changes correctly is a particular problem. It is common to find that necessary changes consequent on some other change have not been made, so that the system is inconsistent and will eventually fail to operate correctly. The paper discusses tools for system maintenance and focuses on the issue of automation. A tool that automatically generates and maintains all the information it needs is presented. To provide more information about the form and extent of the evolution in real-world systems, the same tool was instructed to collect change measurements. Information about the evolution of a large health management system was recorded over a period of 18 months. Methods for and problems of automatic change measurements collection are discussed

Digital Signal Processor Based Real-Time Phased Array Radar Backend System and Optimization Algorithms

This dissertation presents an implementation of multifunctional large-scale phased array radar based on the scalable DSP platform. The challenge of building large-scale phased array radar backend is how to address the compute-intensive operations and high data throughput requirement in both front-end and backend in real-time. In most of the applications, FPGA or VLSI hardware are typically used to solve those difficulties. However, with the help of the fast development of IC industry, using a parallel set of high-performing programmable chips can be an alternative. We present a hybrid high-performance backend system by using DSP as the core computing device and MTCA as the system frame. Thus, the mapping techniques for the front and backend signal processing algorithm based on DSP are discussed in depth. Beside high-efficiency computing device, the system architecture would be a major factor influencing the reliability and performance of the backend system. The reliability requires the system must incorporate the redundancy both in hardware and software. In this dissertation, we propose a parallel modular system based on MTCA chassis, which can be reliable, scalable, and fault-tolerant. Finally, we present an example of high performance phased array radar backend, in which there is the number of 220 DSPs, achieving 7000 GFLOPS calculation from 768 channels. This example shows the potential of using the combination of DSP and MTCA as the computing platform for the future multi-functional large-scale phased array radar

Thesaurus-Based Methodologies and Tools for Maintaining Persistent Application Systems

The research presented in this thesis establishes thesauri as a viable foundation for models, methodologies and tools for change management. Most of the research has been undertaken in a persistent programming environment. Persistent language technology has enabled the construction of sophisticated and well-integrated change management tools; tools and applications reside in the same store. At the same time, the research has enhanced persistent programming environments with models, methodologies and tools that are crucial to the exploitation of persistent programming in construction and maintenance of long-lived, data-intensive application systems