A study of the Zhiqing identity

More than seventeen million Chinese urban youth (Zhiqing in Chinese) went to the countryside, lived and engaged in agricultural work there during the Up to the Mountains and Down to the Countryside (UMDC) Movement (1967-1981). Although this movement was officially terminated in 1981, it has left an imprint on these people – the Zhiqing identity by which they are still characterized as a unique group in Chinese society and a special generation in Chinese history. Historical and sociological perspectives are combined in this study. By applying Glen H. Elder’s life course approach, the study reveals how Zhiqing’s life trajectories are embedded in the social history and identifies a series of interrelated factors that made Zhiqing into a unique generation. With the guidance of Henri Tajfel’s social identity theory, the study uncovers the emergence of the Zhiqing group and the Zhiqing identity, explains individuals’ acquisitions of the Zhiqing identity and analyzes how it has kept influencing individuals’ lives during and after the UMDC Movement. Using Zhiqing’s life stories allowed the researcher to combine the historical and sociological aspects in her examination of Zhiqing’s identity issues. In each life story, the narrator reviewed his/her life experience, reflected on socio-historical changes and expressed his/her emotions and ideas about identity issues. Utilizing methods of in-depth interview and thematic analysis, the researcher completed the study and presents this thesis as one interpretation on the Zhiqing identity, which, as according the researcher’s hermeneutic stance, is open to further discussion and future research.

Subterfuge-safe trust management for delegation of permissions in open environments

Open environments involve distributed entities interacting with each other in an open manner. Many distributed entities are unknown to each other but need to collaborate and share resources in a secure fashion. Usually resource owners alone decide who is trusted to access their resources. Since resource owners in open environments do not have a complete picture of all trusted entities, trust management frameworks are used to ensure that only authorized entities will access requested resources. Every trust management system has limitations, and the limitations can be exploited by malicious entities. One vulnerability is due to the lack of globally unique interpretation for permission specifications. This limitation means that a malicious entity which receives a permission in one domain may misuse the permission in another domain via some deceptive but apparently authorized route; this malicious behaviour is called subterfuge. This thesis develops a secure approach, Subterfuge Safe Trust Management (SSTM), that prevents subterfuge by malicious entities. SSTM employs the Subterfuge Safe Authorization Language (SSAL) which uses the idea of a local permission with a globally unique interpretation (localPermission) to resolve the misinterpretation of permissions. We model and implement SSAL with an ontology-based approach, SSALO, which provides a generic representation for knowledge related to the SSAL-based security policy. SSALO enables integration of heterogeneous security policies which is useful for secure cooperation among principals in open environments where each principal may have a different security policy with different implementation. The other advantage of an ontology-based approach is the Open World Assumption, whereby reasoning over an existing security policy is easily extended to include further security policies that might be discovered in an open distributed environment. We add two extra SSAL rules to support dynamic coalition formation and secure cooperation among coalitions. Secure federation of cloud computing platforms and secure federation of XMPP servers are presented as case studies of SSTM. The results show that SSTM provides robust accountability for the use of permissions in federation. It is also shown that SSAL is a suitable policy language to express the subterfuge-safe policy statements due to its well-defined semantics, ease of use, and integrability.

Quantifying the value of improved wind energy forecasts in a pool-based electricity market

This work illustrates the influence of wind forecast errors on system costs, wind curtailment and generator dispatch in a system with high wind penetration. Realistic wind forecasts of different specified accuracy levels are created using an auto-regressive moving average model and these are then used in the creation of day-ahead unit commitment schedules. The schedules are generated for a model of the 2020 Irish electricity system with 33% wind penetration using both stochastic and deterministic approaches. Improvements in wind forecast accuracy are demonstrated to deliver: (i) clear savings in total system costs for deterministic and, to a lesser extent, stochastic scheduling; (ii) a decrease in the level of wind curtailment, with close agreement between stochastic and deterministic scheduling; and (iii) a decrease in the dispatch of open cycle gas turbine generation, evident with deterministic, and to a lesser extent, with stochastic scheduling.