Distinguishing Views in Symmetric Networks: A Tight Lower Bound

The view of a node in a port-labeled network is an infinite tree encoding all walks in the network originating from this node. We prove that for any integers $n\geq D\geq 1$, there exists a port-labeled network with at most $n$ nodes and diameter at most $D$ which contains a pair of nodes whose (infinite) views are different, but whose views truncated to depth $\Omega(D\log (n/D))$ are identical

Mobile manipulators collision-free trajectory planning with regard to end-effector vibrations elimination

A sub-optimal point-to-point trajectory planning method for mobile manipulators operating in the workspace including obstacles taking into account the damping of the end-effector vibrations is presented. The proposed solution is based on extended Jacobian approach and redundancy resolution at the acceleration level. Fulfilment of the condition stopping the mobile manipulator at the destination point is guaranteed, which leads to elimination of the end-effector vibrations and significantly increases positioning accuracy. The effectiveness of the presented method is shown and compared to the classical Jacobian pseudo inverse approach. A computer example involving a mobile manipulator consisting of a nonholonomic platform (2, 0) class and SCARA-type holonomic manipulator operating in two-dimensional task space including obstacle is also presented

Algorithms and Architecture for Real-time Recommendations at News UK

Recommendation systems are recognised as being hugely important in industry, and the area is now well understood. At News UK, there is a requirement to be able to quickly generate recommendations for users on news items as they are published. However, little has been published about systems that can generate recommendations in response to changes in recommendable items and user behaviour in a very short space of time. In this paper we describe a new algorithm for updating collaborative filtering models incrementally, and demonstrate its effectiveness on clickstream data from The Times. We also describe the architecture that allows recommendations to be generated on the fly, and how we have made each component scalable. The system is currently being used in production at News UK.Comment: Accepted for presentation at AI-2017 Thirty-seventh SGAI International Conference on Artificial Intelligence. Cambridge, England 12-14 December 201

Tetrahedratic mesophases, chiral order, and helical domains induced by quadrupolar and octupolar interactions

We present an exhaustive account of phases and phase transitions that can be stabilized in the recently introduced generalized Lebwohl-Lasher model with quadrupolar and octupolar microscopic interactions [ L. Longa, G. Pająk and T. Wydro Phys. Rev. E 79 040701 (2009)]. A complete mean-field analysis of the model, along with Monte Carlo simulations allows us to identify four distinct classes of the phase diagrams with a number of multicritical points where, in addition to the standard uniaxial and biaxial nematic phases, the other nematic like phases are stabilized. These involve, among the others, tetrahedratic (T), nematic tetrahedratic (NT), and chiral nematic tetrahedratic (NT*) phases of global Td, D2d, and D2 symmetry, respectively. Molecular order parameters and correlation functions in these phases are determined. We conclude with generalizations of the model that give a simple molecular interpretation of macroscopic regions with opposite optical activity (ambidextrous chirality), observed, e.g., in bent-core systems. An estimate of the helical pitch in the NT* phase is also given

Characterisation of human mtRF1 and C12orf65 : what are their roles in mitochondrial protein synthesis?

PhD ThesisMitochondria have their own protein synthesis machinery that synthesises the oxidative phosphorylation components encoded by their mtDNA. This translation process consists of four main phases: initiation, elongation, termination and ribosome recycling. Termination and its control have been the least investigated. Recently, however, the termination factor, mtRF1a, has been characterised as sufficient to release all the nascent proteins from the mitoribosome. Furthermore, bioinformatics has identified three additional members of this mitochondrial release factor family namely, mtRF1, C12orf65 and ICT1. The latter is now known to be incorporated into the mitoribosome but its exact function remains unclear. My project has therefore focussed on characterising the remaining two factors; mtRF1 and C12orf65, and investigating their possible involvement in mitochondrial protein synthesis. It has been demonstrated that protein synthesis is not perfect and bacterial ribosomes not infrequently stall during translation. This can result from limiting amounts of charged tRNAs, stable secondary structures, or truncated/degraded transcripts. Ribosome stalling has been shown to cause growth arrest. In order to prevent that and maintain high efficiency of mitochondrial protein synthesis such stalled complexes need to be rapidly recycled. Bacteria have developed at least three distinct mechanisms by which ribosomes can be rescued. Contrastingly, despite the presence of truncated mRNAs in mitochondria, no such quality control mechanisms have been identified in these organelles. This study investigates the potential role of mtRF1 and C12orf65 in quality control of protein synthesis in mitochondria. Both mtRF1 and C12orf65 demonstrate conservative motifs which would suggest their potential role in ribosome rescue. My findings indicate that the conserved motifs in mtRF1 are crucial to maintain normal cell metabolism and that its mutated forms negatively affect cell growth. Since these motifs are required for ribosome dependent peptidyl-tRNA hydrolysis, the data presented strongly imply that mtRF1 plays a crucial role in intra-organellar protein synthesis.Biotechnology and Biological Sciences Research Council (BBSRC), Centre for Brain Ageing and Vitality (CBAV) and Newcastle University for fundin

A qualitative investigation of patient and staff experience across multiple clinical services: The case of a redevelopment programme at an English acute hospital NHS trust

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This study was a qualitative examination of patient and staff experiences within a redeveloping acute NHS hospital Trust in England. The aim of the investigation was to examine the current direction in government policy which places considerable emphasis upon delivering healthcare services structured broadly around increased patient involvement and choice. There is a need to address the gaps in the evidence for this strategic direction, which indicate an apparent lack of appreciation for the complexities involved. The qualitative methods applied in the study included the use of patient and staff interviews, observations and some documentary review. The research location was selected as an opportunity to assess and compare the perceptions and experiences of patients and staff in the context of a hospital redevelopment programme, from within three distinct clinical services. The three clinical services studied were accident and emergency, a paediatric ambulatory care unit and an adult respiratory outpatient clinic. Thematic content analysis was applied to the data. Findings indicated that generally patients were satisfied with their care and did not expect greater control or involvement. Some issues were raised by staff around uncertainty towards the change programme. Furthermore, there was a suggestion that staff and patients had differing perceptions of what constituted satisfactory care, with respect to technical versus functional quality. The notion of a ‘model’ of patient behaviour emerged. The conclusion is that given the current political agenda focused on the role of the patient, greater sensitivity in understanding towards terms such as patient-centred care, involvement and choice is required. Additionally, there is a need for greater awareness and appreciation of the discrepancy between staff and patient perspectives of what impacts the patient experience. Further research might focus upon the understanding of the patient processes and interactions involved with respect to patient-centred care and choice

End-effector vibrations reduction in trajectory tracking for mobile manipulator

A method of motion planning for a mobile manipulator taking into account damping the end-effector vibrations is presented. The primary task of the robot is to trace a given end-effector trajectory. The redundant degrees of freedom are used to fulfil secondary objectives such as minimisation of platform kinetic energy and maximisation of holonomic manipulability measure, which leads to reduction of the end-effector vibrations. The method is based on Jacobian pseudo inverse at the acceleration level. Nonholonomic constraints in a Pfaffian form are explicitly incorporated to the control algorithm. A computer example involving a mobile manipulator consisting of a nonholonomic platform (2, 0) class and SCARA-type holonomic manipulator operating in two-dimensional task space is also presented