Improving Recurrent Software Development: A Contextualist Inquiry Into Release Cycle Management

Software development is increasingly conducted in a recurrent fashion, where the same product or service is continuously being developed for the marketplace. Still, we lack detailed studies about this particular context of software development. Against this backdrop, this dissertation presents an action research study into Software Inc., a large multi-national software provider. The research addressed the challenges the company faced in managing releases and organizing software process improvement (SPI) to help recurrently develop and deliver a specific product, Secure-on-Request, to its customers and the wider marketplace. The initial problem situation was characterized by recent acquisition of additional software, complexity of service delivery, new engineering and product management teams, and low software development process maturity. Asking how release management can be organized and improved in the context of recurrent development of software, we draw on Pettigrew’s contextualist inquiry to focus on the ongoing interaction between the contents, context and process to organize and improve release cycle practices and outcomes. As a result, the dissertation offers two contributions. Practically, it contributes to the resolution of the problem situation at Software Inc. Theoretically, it introduces a new software engineering discipline, release cycle management (RCM), focused on recurrent delivery of software, including SPI as an integral part, and grounded in the specific experiences at Software Inc

The Transactional Conflict Problem

The transactional conflict problem arises in transactional systems whenever two or more concurrent transactions clash on a data item. While the standard solution to such conflicts is to immediately abort one of the transactions, some practical systems consider the alternative of delaying conflict resolution for a short interval, which may allow one of the transactions to commit. The challenge in the transactional conflict problem is to choose the optimal length of this delay interval so as to minimize the overall running time penalty for the conflicting transactions. In this paper, we propose a family of optimal online algorithms for the transactional conflict problem. Specifically, we consider variants of this problem which arise in different implementations of transactional systems, namely "requestor wins" and "requestor aborts" implementations: in the former, the recipient of a coherence request is aborted, whereas in the latter, it is the requestor which has to abort. Both strategies are implemented by real systems. We show that the requestor aborts case can be reduced to a classic instance of the ski rental problem, while the requestor wins case leads to a new version of this classical problem, for which we derive optimal deterministic and randomized algorithms. Moreover, we prove that, under a simplified adversarial model, our algorithms are constant-competitive with the offline optimum in terms of throughput. We validate our algorithmic results empirically through a hardware simulation of hardware transactional memory (HTM), showing that our algorithms can lead to non-trivial performance improvements for classic concurrent data structures

Causes, Effects, and Remedies in Conflict Management

While workplace conflicts have been widely studied in the literature, this researchprovides a holistic view of the causes and effects of such, and how managers or amanagement can resolve the conflicts among their teams and organization througha detailed, multidimensional framework carried out on one of the biggest textilefirms of Pakistan. With an initial sample of 145 respondents, 37 questionnaireswere dropped because of invalid and incomplete answers; therefore, the studywas carried out on 108 respondents. Conflicts are a part of human nature, butmanagement should play an important role in dealing with these issues, as therecan be enormous chances of conflicts due to a diverse workforce. Conflict alsoresults in poor work performance and low productivity; therefore, it’s suggestedto create teams or groups which may encourage a competitive culture in theorganization. Additionally, a few remedies are identified, which may resolve someissues; managers must look at those techniques for a better culture.&nbsp

Exploiting fatty acid metabolic pathway for production of short chain fatty acids in E. coli

Worldwide demand of sustainable fuels and chemicals has encouraged researchers for microbial synthesis of short chain fatty acids (SCFAs), such as such as butyric acid (C4), as they are attractive precursors to replace petroleum-based fuels and chemicals. In this study, we explored the fatty acid metabolism for production of butyric acid in E. coli with the help of three thioesterases, i.e., TesAT from Anaerococcus tetradius, TesBF from Bryantella formatexigens and TesBT from Bacteroides thetaiotaomicron. We found that E. coli strain transformed with gene for TesBT and grown in presence of 8 g/L glucose produced maximum butyric acid titer at 1.46 g/L, followed by that of TesBF at 0.85 g/L and TesAT at 0.12 g/L, showing that these thioesterases were efficiently converting short chain fatty acyl-ACP into corresponding acid. The titer of butyric acid varied significantly depending upon the strain genotype and plasmid copy number. Deletion of genes involved in initiating the fatty acid degradation such as fatty acyl-CoA synthetase and acyl-CoA dehydrogenase and overexpression of FadR, which is a dual transcriptional regulator, exerts negative control over fatty acid degradation pathway, reduced up to 30% of butyric acid titer. This observation suggested that β-oxidation pathway is working synergistically with fatty acid synthesis pathway in production of butyric acid. Moreover, accelerating the fatty acid elongation cycle by overexpressing acetyl-CoA carboxyltransferase (Acc) and 3-hydroxy-acyl-ACP dehydratase (FabZ) or by deleting FabR, the transcription suppressor of elongation, did not improve the butyric acid titer, rather favored the long chain fatty acid production. Use of chemical inhibitor cerulenin, which limits the fatty acid elongation cycle, increased the butyric acid titer by 1.7-fold in case of TesBF, while it had adverse impact in case of TesBT. In vitro enzyme assay showed that cerulenin also inhibited the short chain specific thioesterases, though inhibitory concentration varied according to the type of thioesterase used. Further improvement in butyric acid was achieved by process optimization. Owing to the same pathway for both cell growth and butyric acid production, a balance was achieved between the two by growing the cells under nutrient and oxygen limiting condition. Keeping these factors in mind, a fed-batch cultivation strategy was devised for production of butyric acid in phosphorous and carbon limiting condition. Finally, we obtained 14.3 g/L of butyric acid and 17.5 g/L of total free fatty acid. The strategy used in this study resulted in highest reported titers of butyric acid and free fatty acids in engineered E. coli and could be used to replace the traditional chemical methods for production of butyric acid