Optimal Scheduling Methods to Integrate Plug-In Electric Vehicles with the Power System: A Review

The introduction of the Tesla in 2008 has demonstrated to the public of the potential of electric vehicles in terms of reducing fuel consumption and green-house gas from the transport sector. It has brought electric vehicles back into the spotlight worldwide at a moment when fossil fuel prices were reaching unexpected high due to increased demand and strong economic growth. The energy storage capabilities from of fleets of electric vehicles as well as the potentially random discharging and charging offers challenges to the grid in terms of operation and control. Optimal scheduling strategies are key to integrating large numbers of electric vehicles and the smart grid. In this paper, state-of-the-art optimization methods are reviewed on scheduling strategies for the grid integration with electric vehicles. The paper starts with a concise introduction to analytical charging strategies, followed by a review of a number of classical numerical optimization methods, including linear programming, non-linear programming, dynamic programming as well as some other means such as queuing theory. Meta-heuristic techniques are then discussed to deal with the complex, high-dimensional and multi-objective scheduling problem associated with stochastic charging and discharging of electric vehicles. Finally, future research directions are suggested.

Is the multiracial congregation an answer to the problem of race? Comparative perspectives from South Africa and the USAF

This paper uses a comparative perspective to analyze how multiracial congregations may contribute to racial reconciliation in South Africa. Drawing on the large-scale study of multiracial congregations in the USA by Emerson et al., it examines how they help transform antagonistic identities and make religious contributions to wider reconciliation processes. It compares the American research to an ethnographic study of a congregation in Cape Town, identifying cross-national patterns and South African distinctives, such as discourses about restitution, AIDS, inequality and women. The extent that multiracial congregations can contribute to reconciliation in South Africa is linked to the content of their worship and discourses, but especially to their ability to dismantle racially aligned power structures. © Koninklijke Brill NV, 2008.

Religion and Transformation in South Africa? Institutional and Discursive Change in a Charismatic Congregation

A number of Christian churches in South Africa have proclaimed their commitment to reconciliation and the elimination of unjust inequalities. This study analyses how these commitments are being worked out at the micro-level of a congregation. Using an ethnographic approach, I explore how a charismatic congregation in Cape Town has changed from being nearly all-white to being more inclusive. I explore links between individual, cognitive identity change and institutional change; and consider the discourses which justify change, including their emphasis on 'unity in diversity' and 'restitution'. I outline the limitations of change, including the persistence of 'racialised' leadership structures and the discursive privileging of unity over restitution. This allows us to understand how micro-level changes take place, to explore their potentialities and limitations, and to apply these insights to other contexts.

The use of YouTube Analytics of Video Lecture Capture as a Teaching and Learning Performance Enhancer

Do patterns in the YouTube viewing analytics of Lecture Capture videos point to areas of potential teaching and learning performance enhancement? The goal of this action based research project was to capture and quantitatively analyse the viewing behaviours and patterns of a series of video lecture captures across several computing modules in Queen’s University, Belfast, Northern Ireland. The research sought to establish if a quantitative analysis of viewing behaviours coupled with a qualitative evaluation of the material provided from the students could be correlated to provide generalised patterns that could then be used to understand the learning experience of students during face to face lectures and, thereby, present opportunities to reflectively enhance lecturer performance and the students’ overall learning experience and, ultimately, their level of academic attainment.

An Adaptive Predictive Control Strategy for RMPPT under Partially Shaded Conditions

As one of key technologies in photovoltaic converter control, Maximum Power Point Tracking (MPPT) methods can keep the power conversion efficiency as high as nearly 99% under the uniform solar irradiance condition. However, these methods may fail when shading conditions occur and the power loss can over as much as 70% due to the multiple maxima in curve in shading conditions v.s. single maximum point in uniformly solar irradiance. In this paper, a Real Maximum Power Point Tracking (RMPPT) strategy under Partially Shaded Conditions (PSCs) is introduced to deal with this kind of problems. An optimization problem, based on a predictive model which will change adaptively with environment, is developed to tracking the global maxima and corresponding adaptive control strategy is presented. No additional circuits are required to obtain the environment uncertainties. Finally, simulations show the effectiveness of proposed method.

Optimization of Controller Parameters for Energy Saving

Among various technologies to tackle the twin challenges of sustainable energy supply and climate change, energy saving through advanced control plays a crucial role in decarbonizing the whole energy system. Modern control technologies, such as optimal control and model predictive control do provide a framework to simultaneously regulate the system performance and limit control energy. However, few have been done so far to exploit the full potential of controller design in reducing the energy consumption while maintaining desirable system performance. This paper investigates the correlations between control energy consumption and system performance using two popular control approaches widely used in the industry, namely the PI control and subspace model predictive control. Our investigation shows that the controller design is a delicate synthesis procedure in achieving better trade-o between system performance and energy saving, and proper choice of values for the control parameters may potentially save a significant amount of energy

On Variable Selection of a Nonlinear Non-parametric System with a Limited Data Set: A Stepwise Algorithm

his paper considers a problem of identification for a high dimensional nonlinear non-parametric system when only a limited data set is available. The algorithms are proposed for this purpose which exploit the relationship between the input variables and the output and further the inter-dependence of input variables so that the importance of the input variables can be established. A key to these algorithms is the non-parametric two stage input selection algorithm.

On Infinite Time Performance of Nonlinear Model Predictive Controllers

This paper addresses the problem of infinite time performance of model predictive controllers applied to constrained nonlinear systems. The total performance is compared with a finite horizon optimal cost to reveal performance limits of closed-loop model predictive control systems. Based on the Principle of Optimality, an upper and a lower bound of the ratio between the total performance and the finite horizon optimal cost are obtained explicitly expressed by the optimization horizon. The results also illustrate, from viewpoint of performance, how model predictive controllers approaches to infinite optimal controllers as the optimization horizon increases.

Control energy consumption and system performance in vector control of voltage source converters

Power electronics plays an important role in the control and conversion of modern electric power systems. In particular, to integrate various renewable energies using DC transmissions and to provide more flexible power control in AC systems, significant efforts have been made in the modulation and control of power electronics devices. Pulse width modulation (PWM) is a well developed technology in the conversion between AC and DC power sources, especially for the purpose of harmonics reduction and energy optimization. As a fundamental decoupled control method, vector control with PI controllers has been widely used in power systems. However, significant power loss occurs during the operation of these devices, and the loss is often dissipated in the form of heat, leading to significant maintenance effort. Though much work has been done to improve the power electronics design, little has focused so far on the investigation of the controller design to reduce the controller energy consumption (leading to power loss in power electronics) while maintaining acceptable system performance. This paper aims to bridge the gap and investigates their correlations. It is shown a more thoughtful controller design can achieve better balance between energy consumption in power electronics control and system performance, which potentially leads to significant energy saving for integration of renewable power sources.

Rapid-bTB: a novel lateral flow test able to differentiate Mycobacterium bovis from Mycobacterium tuberculosis in sputum

Background: A novel lateral flow, immunochromatographic assay (LFD) specific for Mycobacterium bovis, the cause of bovine tuberculosis and zoonotic TB, was recently developed at Queen’s University Belfast. The LFD detects whole M. bovis cells, in contrast to other commercially available LFD tests (BD MGITTM TBc ID, SD Bioline TB Ag MPT 64, Capilia TB-Neo kit) which detect MPT64 antigen secreted during growth. The new LFD test has been evaluated in the veterinary context, and its specificity for M. bovis in the broadest sense (i.e. subsp. bovis, subsp. caprae and BCG) and sensitivity to detect M. bovis in positive MGIT™ liquid cultures was demonstrated comprehensively.
Methods: Preliminary work was carried out by researchers at Queen’s University Belfast to optimise sputum sample preparation, estimate the limit of detection (LOD) of the LFD with M. bovis-spiked sputum samples, and check LFD specificity by testing a broad range of non-tuberculous Mycobacterium spp. (NTM) and other bacterial genera commonly encountered in sputum samples (Haemophilus, Klebsiella, Pseudomonas, Staphylococcus). In the Cameroon laboratory direct detection of M. bovis in human sputa was attempted, and 50 positive sputum MGIT™ cultures and 33 cultures of various Mycobacterium spp. originally isolated from human sputa were tested.
Results: Sputum sample preparation consisted of digestion with 1% NALC for 30 min, centrifugation at 3000g for 20 min, PBS wash, centrifugation again, and pellet resuspended in KPL blocking buffer before 100 µl was applied to the LFD. The LOD of the LFD applied to M. bovis-spiked sputum was estimated to be 104 CFU/ml. A small number of confirmed Ziehl-Neelsen ‘3+’ M. bovis positive sputum samples were tested directly but no positive LFD results were obtained. All of the sputum MGIT™ cultures and mycobacterial cultures (including M. tuberculosis, M. africanum, M. bovis, M. intracellulare, M. scrofulaceum, M. fortuitum, M. peregrinum, M. interjectum) tested LFD negative when read after 15 min except for the M. bovis cultures, thereby confirming specificity of LFD for M. bovis in the clinical microbiology context.
Conclusions: Results indicate that the ‘Rapid-bTB’ LFD is a very specific test, able to differentiate M. bovis from M. tuberculosis, M. africanum, and a range of NTM isolated from human sputa in MGITTM liquid cultures. However, the LFD lacks sufficient sensitivity to be applied earlier in the diagnostic process to directly test human sputa.

The African Pediatric Fellowship Program: Training in Africa for Africans

Africa has a significant burden of childhood disease, with relatively few skilled health care professionals. The African Paediatric Fellowship Programme was developed by the Department of Pediatrics and Child Health at the University of Cape Town to provide relevant training for African child health professionals, by Africans, within Africa. Trainees identified by partner academic institutions spend 6 months to 2 years training in the Department of Pediatrics and allied disciplines. They then return to their home institution to build practice, training, research, and advocacy. From 2008 to 2015, 73 physicians have completed or are completing training in general pediatrics or a pediatric subspecialty. At 1 year posttraining, 98% to 100% are practicing back in their home institution. The impact of the returning fellows is evident from their practice interventions, research collaborations, and positions as stakeholders who can change health care policies. Thirty-three centers in 13 African countries are partners with the program, and the program template is now followed by other partner sites in Africa. Increasing and retaining the skills pool of African child health specialists is building a network of motivated, highly skilled clinicians who are equipped to advance child health in Africa.

Extracting bridge frequencies from dynamic responses of two passing vehicles

A conventional way to identify bridge frequencies is utilizing vibration data measured directly from the bridge. A drawback with this approach is that the deployment and maintenance of the vibration sensors are generally costly and time-consuming. One of the solutions is in a drive-by approach utilizing vehicle vibrations while the vehicle passes over the bridge. In this approach, however, the vehicle vibration includes the effect of road surface roughness, which makes it difficult to extract the bridge modal properties. This study aims to examine subtracting signals of two trailers towed by a vehicle to reduce the effect of road surface roughness. A simplified vehicle-bridge interaction model is used in the numerical simulation; the vehicle - trailer and bridge system are modeled as a coupled model. In addition, a laboratory experiment is carried out to verify results of the simulation and examine feasibility of the damage detection by the drive-by method.