THE EVOLUTION OF PROCESS MODELS IN IS RESEARCH: FROM A PUNCTUATED SOCIAL PROCESS MODEL TO A SOCIO-TECHNICAL PROCESS MODEL

The implementation of information technology and its association with organizational change has been an important theme in the Information Systems (IS) literature over the past 30 years. The progression of variance and process theories provide an in-depth overview of the emergence of richer accounts of IS change. In this paper we chronicle the evolution of process models and related theory. We also show how the application of process thinking in IS research has improved our understanding of complex IS change. These models depict more faithfully actors’ lived experiences and preserve the details and essential effects of critical events. An emerging benefit the process models is the capability to identify common patterns in a project’s evolutionary trajectory

Metadata-Aware Query Processing over Data Streams

Many modern applications need to process queries over potentially infinite data streams to provide answers in real-time. This dissertation proposes novel techniques to optimize CPU and memory utilization in stream processing by exploiting metadata on streaming data or queries. It focuses on four topics: 1) exploiting stream metadata to optimize SPJ query operators via operator configuration, 2) exploiting stream metadata to optimize SPJ query plans via query-rewriting, 3) exploiting workload metadata to optimize parameterized queries via indexing, and 4) exploiting event constraints to optimize event stream processing via run-time early termination. The first part of this dissertation proposes algorithms for one of the most common and expensive query operators, namely join, to at runtime identify and purge no-longer-needed data from the state based on punctuations. Exploitations of the combination of punctuation and commonly-used window constraints are also studied. Extensive experimental evaluations demonstrate both reduction on memory usage and improvements on execution time due to the proposed strategies. The second part proposes herald-driven runtime query plan optimization techniques. We identify four query optimization techniques, design a lightweight algorithm to efficiently detect the optimization opportunities at runtime upon receiving heralds. We propose a novel execution paradigm to support multiple concurrent logical plans by maintaining one physical plan. Extensive experimental study confirms that our techniques significantly reduce query execution times. The third part deals with the shared execution of parameterized queries instantiated from a query template. We design a lightweight index mechanism to provide multiple access paths to data to facilitate a wide range of parameterized queries. To withstand workload fluctuations, we propose an index tuning framework to tune the index configurations in a timely manner. Extensive experimental evaluations demonstrate the effectiveness of the proposed strategies. The last part proposes event query optimization techniques by exploiting event constraints such as exclusiveness or ordering relationships among events extracted from workflows. Significant performance gains are shown to be achieved by our proposed constraint-aware event processing techniques

Institutional Theories and Public Institutions.

This chapter covers the evolution of institutional theory and its application to public adminsitrations in the last 20 years. It discusses the various streams, their reseach agendas and their contributions, but also their limits to add value to knowledge.New institutional theories: historical, sociological, "new institutionalism", co-constructed local orders.

Social Movements, Public Policy, and Democratic Consolidation in Latin America

This work studies how different social mobilisation processes have influenced policy processes in Latin America (2000-2003) and vice versa. Studying these interrelations includes three issues of empirical and theoretical importance. First, it explores under what conditions an investment project or policy initiative that is strongly supported by a democratically elected government on the basis of economic and technical arguments may trigger the emergence of a social movement; and under what conditions a social movement may successfully preclude the implementation of such project or policy initiative. Second, this work explores if these social movements have actually compensated for the absence of channels of participation and representation that work to influence the institutional policy process. Third and final, it studies if the influence and impact of these social movements have contributed to improve the design and implementation of public policies in the medium term and to promote the democratic consolidation in the region. Although the work is based on evidence from many countries in the region, there are mainly two case studies presented with more detail: the 'Water War' in Cochabamba, Bolivia (2001-2002) and the conflict triggered by the project to build a new airport in Mexico City (2001-2002). The 'Gas War' of Bolivia (2003) is also explored with less detail.

A Comparative Examination of the Nature of Change in Macroeconomic Policies

This article examines the impact of economic crises on macroeconomic policies in Ireland in the late 1950s and Sweden in the early 1980s, framed within the context of the policy change literature. Each of these countries? responses to the crises affecting them, tempered as they were by historical and political factors, provides valuable insights into their political economies. These findings enable us to compare and contrast the nature of each crisis and the policy responses adopted. The value of such comparison is in the perspective it offers, contributing to the goal of building a body of increasingly complete explanatory theory (Mahler, 1995).

Water temperature dynamics in High Arctic river basins

Despite the high sensitivity of polar regions to climate change and the strong influence of temperature upon ecosystem processes, contemporary understanding of water temperature dynamics in Arctic river systems is limited. This research gap was addressed by exploring high-resolution water column thermal regimes for glacier-fed and non-glacial rivers at eight sites across Svalbard during the 2010 melt season. Mean water column temperatures in glacier-fed rivers (0.3-3.2 °C) were lowest and least variable near the glacier terminus but increased downstream (0.7-2.3 °C km ). Non-glacial rivers, where discharge was sourced primarily from snowmelt runoff, were warmer (mean: 2.9-5.7 °C) and more variable, indicating increased water residence times in shallow alluvial zones and increased potential for atmospheric influence. Mean summer water temperature and the magnitude of daily thermal variation were similar to those of some Alaskan Arctic rivers but low at all sites when compared with alpine glacierized environments at lower latitudes. Thermal regimes were correlated strongly (p<0.01) with incoming short-wave radiation, air temperature, and river discharge. Principal drivers of thermal variability were inferred to be (i) water source (i.e. glacier melt, snowmelt, groundwater); (ii) exposure time to the atmosphere; (iii) prevailing meteorological conditions; (iv) river discharge; (v) runoff interaction with permafrost and buried ice; and (vi) basin-specific geomorphological features (e.g. channel morphology). These results provide insight into the potential changes in high-latitude river systems in the context of projected warming in polar regions. We hypothesize that warmer and more variable temperature regimes may prevail in the future as the proportion of bulk discharge sourced from glacial meltwater declines and rivers undergo a progressive shift towards snow water and groundwater sources. Importantly, such changes could have implications for aquatic species diversity and abundance and influence rates of ecosystem functioning in high-latitude river systems