Hydro/Battery Hybrid Systems for frequency regulation

An innovative Hydro/Battery Hybrid System (HBHS), composed of a hydropower plant (HPP) and a Battery Energy Storage System (BESS) is proposed to provide frequency regulation services in the Nordic Power System (NPS). The HBHS is envisioned to have a faster and more efficient response compared to HPPs currently providing these services, whilst retaining their high energy capacity and endurance, thus alleviating stand-alone BESS operation constraints. This Thesis aims to explore the operation and optimization of such a hybrid system in order to make it efficient and economically viable. A power plant perspective is employed, evaluating the impact different control algorithms and parameters have on the HBHS performance. Providing Frequency Containment Reserves for Normal Operation (FCR-N), to the national TSO in Sweden, is defined from technology and market analyses as the use case for the HBHS. The characteristics of HPPs suitable for HBHS implementation are found theoretically, by evaluating HPP operational constraints and regulation mechanisms. With the aim of evaluating the dynamic performance of the proposed HBHS, a frequency regulation model of the NPS is built in MATLAB and Simulink. Two different HBHS architectures are introduced, the Hydro Recharge, in which the BESS is regulating the frequency and the HPP is controlling its state of charge (SoC), and the Frequency Split, in which both elements are regulating the frequency with the HPP additionally compensating for the SoC. The dynamic performance of the units is qualitatively evaluated through existing and proposed FCR-N prequalification tests, prescribed by the TSO and ENTSO-E. Quantitative performance comparison to a benchmark HPP is performed with regards to the estimated HPP regulation wear and tear and BESS degradation during 30-day operation with historical frequency data. The two proposed HBHS architectures demonstrate significant reductions of estimated HPP wear and tear compared to the benchmark unit. Simulations consistently report a 90 % reduction in the number of movements HPP regulation mechanism performs and a more than 50 % decrease in the distance it travels. The BESS lifetime is evaluated at acceptable levels and compared for different architectures. Two different applications are identified, the first being installing the HBHS to enable the HPP to pass FCR-N prequalification tests. The second application is increasing the FCR-N capacity of the HPP by installing the HBHS. The Frequency Split HBHS shows more efficient performance when installed in the first application, as opposed to the Hydro Recharge HBHS, which shows better performance in the second application. Finally, it is concluded that a large-scale implementation of HBHSs would improve the frequency quality in the NPS, linearly decreasing the amount of time outside the normal frequency band with increasing the total installed HBHS power capacity

Platform for Testing and Evaluation of PUF and TRNG Implementations in FPGAs

Implementation of cryptographic primitives like Physical Unclonable Functions (PUFs) and True Random Number Generators (TRNGs) depends significantly on the underlying hardware. Common evaluation boards offered by FPGA vendors are not suitable for a fair benchmarking, since they have different vendor dependent configuration and contain noisy switching power supplies. The proposed hardware platform is primary aimed at testing and evaluation of cryptographic primitives across different FPGA and ASIC families. The modular platform consists of a motherboard and exchangeable daughter board modules. These are designed to be as simple as possible to allow cheap and independent evaluation of cryptographic blocks and namely PUFs. The motherboard is based on the Microsemi SmartFusion 2 SoC FPGA. It features a low-noise power supply, which simplifies evaluation of vulnerability to the side channel attacks. It provides also means of communication between the PC and the daughter module. Available software tools can be easily customized, for example to collect data from the random number generator located in the daughter module and to read it via USB interface. The daughter module can be plugged into the motherboard or connected using an HDMI cable to be placed inside a Faraday cage or a temperature control chamber. The whole platform was designed and optimized to fullfil the European HECTOR project (H2020) requirements

'The Art of Movement in Education Work and Recreation'

Produced by the Laban Art of Movement Guild

Dutch Study Iraqi Asylum Seekers: Impact of a long asylum procedure on health and health related dimensions among Iraqi asylum seekers in the Netherlands; An epidemiological study

Jong, J.T.V.M. [Promotor]de Komproe, I.H. [Promotor]Gernaat, H.B.P.E. [Copromotor

An analytical tale of the social media discursive enactment of networked everyday resistance during the #feesmustfall social movement in South Africa

Social media are a space for discussions, debates and deliberations about personality, culture, society, and actual experiences of social actors in South Africa. They offer an unexpected opportunity for the broader consideration and inclusion of community members’ voices in governance decision making and policy processes. They also offer opportunities to engage, mobilise and change people and society in impressive scale, speed and effect: They have mobilising and transformative powers emanating from their interaction with the impetus of the agency of community members seeking better conditions of living. The magnitude of the effects of these powers makes it imperative to have a better understanding of their workings. Social media have been used in numerous social movements as the medium of communication to mobilise, coordinate, and broadcast protests. However, social media were never a guarantee of success as most movements using them did not achieve significant results. Yet, governments in developed and developing countries tend to engage inadequately with social media supported movements. The research problem is that the contribution of social media to the transformation of the social practice of discourse, which causes SSA community members’ agential impetus (collective intentionality for action) to generate a discourse of resistance on social media during social movements, is not well understood. The main research question is: Why are South African community members using social media to enact online discursive resistance during social movements? The aim of the research is to explain, from a critical realism point of view, Sub-Saharan African community members’ emergent usage of social media during social movements, by providing a contextualised social history (a tale) of South African community members’ practice of online discursive enactment of resistance. The emergent usage of social media of concern is conceptualised as “discursive enactment of networked everyday resistance” within a dialectical space of interaction conceptualised as “space of autonomous resistance”; an instance of a communication space allowing for transformative negation to occur. The research follows Bhaskar’s Critical Realism as a philosophical paradigm. Critical Realism seeks to explain phenomena by retroducing (retrospective inference) causal explanations from empirically observable phenomena to the generative mechanisms which caused them. The research was designed as a qualitative, processual and retroductive inquiry based on the Morphogenetic/Morphostasis approach with two phases: an empirical research developing the case of South African community members’ emergent usage of social media during the #feesmustfall social movement, looking for demi-regularities in social media discourse; and a transcendental research reaching into the past to identified significant events, objects and entities which tendencies are responsible for the shape of observed discourse. In the first phase, a case study was developed from data collected on the social media platform Twitter™, documents, and in-depth interviews of South African community members. The data collected were analysed using qualitative content analysis (QCA) and Critical Discourse Analysis (CDA) to unveil demi-regularities; moving from the observable individual strategic orientation of messages to discourses, thus to the tendencies of relational emergent properties of systemic magnitude which structure local discourses and are transformed by them. Then, the social mediainduced morphogenesis or transformation of South African community members’ discursive action was postulated in an analytical history of emergence (or analytical tale) of their usage of social media within a “space of autonomous resistance” during social movements. The findings of the research suggest that South African community members authored 3 discourses of resistance on Twitter™: #feesmustfall discourses of struggle, identity and oppression. They identified as “student qua black-child” stepping into the “Freedom fighter” role against the hegemonic post-apartheid condition curtailing their aspirations. It was found that social media socio-cultural embeddedness and under-design (Western European socio-cultural globalising underpinning features and functional features of the platforms) which interaction with the local socio-cultural mix (postapartheid socio-cultural tendencies for domination/power, spiral of silence, and legitimacy/identification) resulted in misfits and workarounds enhancing individual emotional conflict and aligning towards a socio-cultural opportunistic contingent complementarity integration in the deployment of discourse. That integration was actualised as a mediatization emergent property through asignification/signification of mainstream discourses of liberal democracy, colonial capitalism, national democratic revolution, free and decolonised education, black consciousness and Fallism. That mediatization through re-signification of the struggle for freedom created a communication “space of autonomous resistance” where networked freedom fighters enacted discursive everyday resistance against the hegemonic forces of students’ precariousness. The contribution of the research includes a realist model of social media discursive action (ReMDA); an explanation of South African community members’ deployment of discourse over social media during social movement and telling the tale of the transformation of discursive practices with the advent of social media in South Africa

Diagnosis and management of dementia

No Abstract