There are three assumptions in the field of psychology about Transactional Analysis that are examined in this thesis: first, TA has an identifiable language, composed of common, easily understood terms; second, it is assumed that people who wish to use TA theory must first learn the language; third, once the language is learned, it is thought that these people can put it to use in their lives.

Software Transactional Memory is a promising approach to concurrent program- ming, freeing programmers from error-prone concurrency control decisions that are complicated and not composable. But few such systems address consistencies of transactional objects. In this thesis, I propose a contract-based transactional programming model toward more secure transactional sofwares. In this general model, a validity contract spec- ifies both requirements and effects for transactions. Validity contracts bring nu- merous benefits including reasoning about and verifying transactional programs, detecting and resolving transactional conflicts, automating object revalidation and easing program debugging. I introduce an ownership-based framework, namely AVID, derived from the gen- eral model, using object ownership as a mechanism for specifying and reasoning validity contracts. I have specified a formal type system and implemented a pro- totype type checker to support static checking. I also have built a transactional library framework AVID, based on existing Java DSTM2 framework, for express- ing transactions and validity contracts. Experimental results on a multi-core system show that contracts add little over- heads to the original STM. I find that contract-aware contention management yields significant speedups in some cases. The results have suggested compiler- directed optimisation for tunning contract-based transactional programs. My further work will investigate the applications of transaction contracts on various aspects of TM research such as hardware support and open-nesting.

Thesis (M.S.)--University of Michigan, 1975.

Thesis (M.S.)--University of Michigan, 1975.

Thesis (M.S.)--University of Michigan, 1975.

The distributed transactional memory (DTM) abstraction aims to simplify the development of distributed concurrent programs. It frees programmers from the complicated and error-prone task of explicit concurrency control based on locks (e.g., deadlocks, livelocks, non-scalability, non-composability), which are aggravated in a distributed environment due to the complexity of multi-node concurrency. At its core, DTM's atomic section-based synchronization abstraction enables the execution of a sequence of multi-node object operations with the classical serializability property, which significantly increases the programmability of distributed systems. In this thesis, we present the first ever DTM framework for distributed concurrency control in C++, called HyflowCPP. HyflowCPP provides distributed atomic sections, and pluggable support for concurrency control algorithms, directory lookup protocols, contention management policies, and network communication protocols. The framework uses the Transaction Forwarding Algorithm (or TFA) for concurrency control. While there exists implementations of TFA and other DTM concurrency control algorithms in Scala and Java, and concomitant DTM frameworks (e.g., HyflowJava, HyflowScala, D2STM, GenRSTM), HyflowCPP provides a uniquely distinguishing TFA/DTM implementation for C++. Also, HyflowCPP supports strong atomicity, transactional nesting models including closed and open nesting (supported using modifications to TFA), and checkpointing. We evaluated HyflowCPP through an experimental study that measured transactional throughput for a set of micro- and macro-benchmarks, and comparing with competitor DTM frameworks. Our results revealed that HyflowCPP achieves up to 600% performance improvement over competitor Java DTM frameworks including D2STM, GenRSTM, HyflowScala and HyflowJava, which can be attributed to the competitors' JVM overhead and rudimentary networking support. Additionally, our experimental studies revealed that checkpointing achieves up to 100% performance improvement over flat nesting and 50% over closed nesting. Open nesting model achieves up to 140% performance improvement over flat nesting and 90% over closed nesting. / Master of Science

The research in this thesis investigates the learning processes of absorptive capacity (AC) as an element within organisation innovation. An analysis of leadership ‘styles’ is undertaken and factors for effective innovation adoption are considered. It is apparent that AC has been well researched in recent years but there is evidence that little attention has been given into important influences such as leadership. Consequently, AC is determined to involve managerial learning through three processes. These include: (1) exploratory learning as an ability to value and acquire external knowledge, (2) transformative learning to assimilate this knowledge, and (3) exploitative learning to use knowledge for innovation. However, there is little known about interventions of AC learning towards innovation and the effects of top and middle managers’ leadership styles on these processes. Therefore, the research initially attempts to investigate the relationship between AC, innovation, and leadership styles with a view to exploring valuable theoretical insights into the learning processes involved. A conceptual model is formulated which suggests a relationship between the learning processes of AC with different stages of innovation adoption. In this respect, the role of managers is investigated through attention to ‘transformational’ and ‘transactional’ leadership styles where the former changes employees’ values for achieving common goals and the latter encourages exiting practices. The methodology adopted involved a qualitative strategy with data collected through three substantive case studies from research sites in Iran. In total 31 Semi-structured interviews were conducted with respondents to explore the learning processes of AC and leadership styles on innovation. Secondary documents and non-participant observations provided further insights by triangulating the data. Data was analysed in two stages (i) a description of each case was reported (ii) a thematic analysis was used in order to compare the case companies collectively. The findings supported the effects of the learning processes of AC on innovation adoption. It was also found that the leadership behaviours of top and middle managers change from transformational to transactional leadership styles during the exploitative learning process. The influence of top managers’ knowledge, middle managers’ intention, and trust in middle managers also emerged as important constructs in the learning processes. The research contributed to the learning processes of AC and the influence of managerial leadership styles by adding new insights to organisational theory. The results will also be of value to practitioners by providing prescriptive analysis when using external knowledge effectively for adopting innovation.

Many parallelization systems detect memory access conflicts across concurrent threads by disambiguating address-sets using bit-vector-based Bloom filters, which are efficient, but can report false conflicts that do not exist. Systems with lazy conflict detection often use Bloom filters unconventionally by testing sets for null-intersection via Bloom filter intersection, contrasting with the conventional approach of issuing membership queries into the Bloom filter. In this dissertation we develop much-needed theory for probability of false conflicts in Bloom filter null-intersection tests, notably demonstrating that Bloom filter intersection requires substantially larger bit-vectors to provide equivalent statistical behavior to querying. Furthermore, we recognize that our theoretical implications counter practical intuition, and thus use RingSTM to evaluate theory in practice by implementing and comparing the Bloom filter configurations. We find that despite its overheads, the queue-of-queries approach reduces execution time and is thus the most compelling alternative to Bloom filter intersection for lazy address-set disambiguation.

Many parallelization systems detect memory access conflicts across concurrent threads by disambiguating address-sets using bit-vector-based Bloom filters, which are efficient, but can report false conflicts that do not exist. Systems with lazy conflict detection often use Bloom filters unconventionally by testing sets for null-intersection via Bloom filter intersection, contrasting with the conventional approach of issuing membership queries into the Bloom filter. In this dissertation we develop much-needed theory for probability of false conflicts in Bloom filter null-intersection tests, notably demonstrating that Bloom filter intersection requires substantially larger bit-vectors to provide equivalent statistical behavior to querying. Furthermore, we recognize that our theoretical implications counter practical intuition, and thus use RingSTM to evaluate theory in practice by implementing and comparing the Bloom filter configurations. We find that despite its overheads, the queue-of-queries approach reduces execution time and is thus the most compelling alternative to Bloom filter intersection for lazy address-set disambiguation.

D.Comm. / The globalisation of the South African economy since 1994 has emphasised the need for a new form of leadership, with specific emphasis on authentic and transformational leadership. By understanding the psychodynamic aspects that drive the transformational leader organisations will be able to identify and develop transformational leaders. A real need exists to understand the psychodynamic attributes of transformational leaders and how these attributes affect their behaviour and effectiveness. Most of the currently available research on psychodynamic attributes and their relationship with leadership behaviour and effectiveness is one-dimensional in nature: the research has investigated one or at most two, stand-alone psychodynamic attributes of leaders and their relationship with transformational leadership behaviour and leader effectiveness.