RT-OMT: A Real-time Object Modeling Technique for Designing Real-time Database Applications: A Position Paper

ABSTRAC

Enhancing the Process of Testing Object -Oriented Systems.

Testing is a crucial step in the overall system development process. Using testing techniques that support features of the underlying software paradigm more effectively tests program than do testing techniques that support features of other paradigms. Systems developed with the object-oriented paradigm require techniques that support object-oriented features such as inheritance, data abstraction, encapsulation, and dynamic binding. Many techniques that are used to test systems developed with the structured paradigm are not sufficient for the testing of object-oriented systems. The goal of this research is to develop methods that will improve the process of testing object-oriented systems. Specifically, emphasis is given to improving the level of testing of methods because the level of method testing is generally considered inadequate. Algorithms are included that identify the set of methods, both interobject and intraobject, that should be tested for a given system. These algorithms are implemented as a part of an automated testing system that derives a framework for the testing of methods. This system includes the automatic generation of test drivers to facilitate the testing. It captures the results of tests for the purposes of reuse for future system maintenance. This framework provides the software engineer who is testing a system a mechanism to determine the level of method coverage that has been achieved in the testing process

A petri-net based methodology for modeling, simulation, and control of flexible manufacturing systems

Global competition has made it necessary for manufacturers to introduce such advanced technologies as flexible and agile manufacturing, intelligent automation, and computer-integrated manufacturing. However, the application extent of these technologies varies from industry to industry and has met various degrees of success. One critical barrier leading to successful implementation of advanced manufacturing systems is the ever-increasing complexity in their modeling, analysis, simulation, and control. The purpose of this work is to introduce a set of Petri net-based tools and methods to address a variety of problems associated with the design and implementation of flexible manufacturing systems (FMSs). More specifically, this work proposes Petri nets as an integrated tool for modeling, simulation, and control of flexible manufacturing systems (FMSs). The contributions of this work are multifold. First, it demonstrates a new application of PNs for simulation by evaluating the performance of pull and push diagrams in manufacturing systems. Second, it introduces a class of PNs, Augmented-timed Petri nets (ATPNs) in order to increase the power of PNs to simulate and control flexible systems with breakdowns. Third, it proposes a new class of PNs called Realtime Petri nets (RTPNs) for discrete event control of FMS s. The detailed comparison between RTPNs and traditional discrete event methods such as ladder logic diagrams is presented to answer the basic question \u27Why is a PN better tool than ladder logic diagram?\u27 and to justify the PN method. Also, a conversion procedure that automatically generates PN models from a given class of logic control specifications is presented. Finally, a methodology that uses PNs for the development of object-oriented control software is proposed. The present work extends the PN state-of-the-art in two ways. First, it offers a wide scope for engineers and managers who are responsible for the design and the implementation of modem manufacturing systems to evaluate Petri nets for applications in their work. Second, it further develops Petri net-based methods for discrete event control of manufacturing systems

Facilitating Emerging Non-volatile Memories in Next-Generation Memory System Design: Architecture-Level and Application-Level Perspectives

This dissertation focuses on three types of emerging NVMs, spin-transfer torque RAM (STT-RAM), phase change memory (PCM), and metal-oxide resistive RAM (ReRAM). STT-RAM has been identified as the best replacement of SRAM to build large-scale and low-power on-chip caches and also an energy-efficient alternative to DRAM as main memory. PCM and ReRAM have been considered to be promising technologies for building future large-scale and low-power main memory systems. This dissertation investigates two aspects to facilitate them in next-generation memory system design, architecture-level and application-level perspectives. First, multi-level cell (MLC) STT-RAM based cache design is optimized by using data encoding and data compression. Second, MLC STT-RAM is utilized as persistent main memory for fast and energy-efficient local checkpointing. Third, the commonly used database indexing algorithm, B+tree, is redesigned to be NVM-friendly. Forth, a novel processing-in-memory architecture built on ReRAM based main memory is proposed to accelerate neural network applications

Dynamic enterprise modelling: a methodology for animating dynamic social networks

PhD ThesisSince the introduction of the Internet and the realisation of its potential companies have either transformed their operation or are in the process of doing so. It has been observed, that developments in I.T., telecommunications and the Internet have boosted the number of enterprises engaging into e-commerce, e-business and virtual enterprising. These trends are accompanied by re-shaping, transformation and changes in an enterprise's boundaries. The thesis gives an account of the research into the area of dynamic enterprise modelling and provides a modelling methodology that allows different roles and business models to be tested and evaluated without the risk associated with committing to a change

Metabolic engineering strategies for high-level production of aromatic amino acid pathway derivatives in Saccharomyces cerevisiae

Due to its robustness, genetic tractability, and industrial relevance, the budding yeast Saccharomyces cerevisiae was selected as study model of the aromatic amino acid biosynthetic pathway. This pathway houses a wide diversity of economically important metabolites ranging from polymer precursors to pain-management drugs, whose productions have been highly sought-after in biotechnological research. However, tight regulations at the transcriptional, translational, and allosteric levels surround the aromatic amino acid pathway, protecting the microbial factories (e.g. S. cerevisiae) from unnecessary energy expenditures. By making use of computational metabolic engineering tools such as Flux Balance Analysis and Metabolic Flux Analysis, together with fast and reliable synthetic biology techniques, the flux into the aromatic amino acid pathway was exploited. Initially, the flux distribution in the central carbon metabolism was studied through 13C-metabolic flux analysis and carbon tracing experiments. Important insights regarding the partition between glycolysis and the pentose phosphate pathway were obtained and correlated with the production of aromatic amino acid derivatives. For the first time, the pentafunctional enzyme, ARO1, composing the core of the shikimic acid pathway was subjected to site-directed mutagenesis to reveal its active domains. This resulted in the development of new variants with disrupted activities specifically designed for increasing production of the two target molecules, namely, muconic acid and shikimic acid. Further analysis with OptForce simulations revealed that overexpressing the ribose-5-phosphate ketol-isomerase gene, RKI1, can enhance carbon funneling into the aromatic amino acid pathway. A multilevel engineering strategy was established to explore novel transcriptional regulators that tightly control the carbon flux into the pathway. Deleting the gene RIC1, involved in efficient protein localization of trans-Golgi network proteins, increased the titers of shikimic acid and muconic acid. These non-intuitive interventions, in combination with the previous genetic platforms, increased the production titers over 3-fold compared to the base strains. The shikimic acid strains produced 1.9 g L-1, while muconic acid and intermediates were accumulated up to 1.6 g L-1, both being the highest reported in S. cerevisiae, in batch fermentations. Future research should focus on devising more dynamic genome engineering strategies that rely on modulating the activity of essential genes while ensuring a good compromise with biomass formation