Dynamic buffer tuning: an ambience-intelligent way for digital ecosystem success

Ambient intelligence is an important element for the success of digital ecosystems which usually are made up of many collaborating distributed nodes. The operations of these nodes affect one another as chain reactions. When one node had failed, it could bring down the whole ecosystem. Dynamic buffer tuning is an ambience-intelligent mechanism because it has the ability to sense the ambient changes and then makes necessary proactive changes on the fly to avoid buffer overflow. As a result the end-to-end communication channel is more dependable, leading to shorter response time and happier clients. Therefore, dynamic buffer tuning should be generally beneficial to digital ecosystem system performance. In this paper we demonstrate this point by using the FLC (Fuzzy Logic Controller) dynamic buffer tuner to quicken the pervasive medical consultation response of the TCM (Traditional Chinese Medicine) Pervasive Digital HealthCare System as an example

E-Macsc: A Novel Dynamic Cache Tuning Technique to Maintain the hit ratio prescribes by the user in internet applications

Department of ComputingRefereed conference pape

An Investigation of a Zero-Net-Mass-Flux Jet in Cross Flow using PIV

Zero-Net-Mass-Flux Jets in cross flow can be used in a number of engineering applications, such as combustion in a gas turbine engine and the cooling of turbine blades. ZNMF-Jets have been seen to create two distinct flow regimes when impinging into a flow, either singular or multiple trajectories as characterised by the Strouhal Number. This paper shows two cases for a ZNMFJet in Cross-flow, when the flow is singular and when the flow shows multiple trajectories, using Digital Particle Image Velocimetry (DPIV). Time and Phase-averaged experiments were conducted in a vertical water tunnel, where the ZNMF-Jet was created using a stepper motor scotch-yoke piston arrangement of cylinder diameter 20mm to force fluid through a 10mm circular jet orifice. The Strouhal Number was taken at 0.11 and 0.56 with the Reynolds Number held constant at 1066 and the velocity ratio between the free stream and the r.m.s. fluctuating velocities of the ZNMF - Jet also held constant at 2. The depth of penetration of the ZNMF–Jet into the cross flow decreases with an increase in Strouhal Number, while the strength of the vortical structures increases with increasing Strouhal Number

‘Voodoo maths’, asymmetric dependency and maths blame: Why collaboration between school science and mathematics teachers is so rare

This is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge) via the DOI in this record.Mathematical reasoning and tools are intrinsic to science, yet the close and dependent relationship science has to mathematics is not reflected in either school education or science education research. This paper asks what the barriers are to a mutually beneficial relationship between the two disciplines. A two-phase qualitative interview study was used to explore the relationship between school science and mathematics education through the perspectives of science and mathematics education policy-makers and of teachers in departments which are unusual in collaborating. In total there were 36 participants. Interview data was were analysed using thematic analysis. Findings show that there is an asymmetry in the dependency between school science and mathematics: science is dependent on mathematics but the reverse is not true. We discuss three consequences of this asymmetric dependency: there is greater benefit for science from any collaboration; ‘maths blame’ can arise from science teacher frustration; and science educators may believe they should have some ownership of the mathematics curriculum. Asymmetry of dependency, and therefore of benefit, will make it very difficult for mathematics and science to work together in a way which is genuinely mutually beneficial

Crossing the boundaries: collaborations between mathematics and science departments in English secondary (high) schools

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record Background There are frequent calls in the literature for school science and mathematics departments to collaborate, largely in response to perceived overlaps and similarities between the two subjects in the context of Science, Technology, Engineering and Mathematics (STEM). Yet few studies explore how such collaborations might work. This paper is unusual both in its focus on mathematics/science collaborations which have not arisen from a specific short-term intervention and in its focus on the views of practising teachers rather than policy-makers or curriculum developers. Purpose We ask how and why collaborations get started and explore how mathematics and science departments actually work together in secondary (high) schools in England. We ask what some of the affordances and challenges are in both initiating and sustaining collaborative practice. Design and methods After a prolonged search for collaborations, six schools were identified and visited and semi-structured interviews carried out with the 15 teachers most closely involved in collaborating, to explore their perspectives and insights. Results The findings show that collaborations are possible, though they are challenging to sustain, and they can be approached in a number of ways. Mathematics/science collaboration can be a key site of professional learning for teachers, particularly about the ‘other’ curriculum. Informal conversations across departments were highly valued but tended to be between those with a well-established pre-existing relationship. While physical structures can support collaboration, it needs strong support from senior leadership teams to begin and can cease if that support stops. Conclusion Contrary to the commonly espoused view that there are many overlaps and similarities between mathematics and science in school, it can be a significant challenge for teachers to find them. Collaboration is neither straightforward to begin nor to sustain. Researchers and policy-makers should thus be cautious about recommending collaboration as straightforward for science and mathematics teachers to adopt. These conclusions provide a major challenge to simplistic advocacy of STEM in schools.Rosalind Driver Research Scholarship Fund at King’s College London

Cylinder Wake – Boundary Layer Interaction in the Near Field

The interaction between the wake generated from separation off a cylinder and turbulent structures evident in a boundary layer are of significant importance in understanding the flows for cooling towers, submerged and semi-submerged vessels. This investigation was conducted on a wall mounted circular cylinder 25.4mm in diameter in the near wake region using MCCDPIV (multi-grid cross correlation digital particle image velocimetry) using a PCO4000 CCD array with full resolution of 4008 x 2672 pixels2 per image. The investigation was conducted for (ReD ≡ DU / ν) of 3600 and 5400. It was seen in the mean after taking the ensemble average of the instantaneous results that a stagnation line was formed between x / D = 1 and 1.5 downstream of the cylinder. The region of the cavity wake was highly turbulent having the largest velocity fluctuations in this region. The shape of the stagnation line was also seen to change, where for the ReD = 3600 the stagnation line position from the cylinder changed for a given height above the flat plate surface at y / D = 0

Insulators at Fractional Fillings in Twisted Bilayer Graphene Partially Aligned to Hexagonal Boron Nitride

At partial fillings of its flat electronic bands, magic-angle twisted bilayer graphene (MATBG) hosts a rich variety of competing correlated phases that show sample to sample variations. Divergent phase diagrams in MATBG are often attributed to the sublattice polarization energy scale, tuned by the degree of alignment of the hexagonal boron nitride (hBN) substrates typically used in van der Waals devices. Unaligned MATBG exhibits unconventional superconductivity and correlated insulating phases, while nearly perfectly aligned MATBG/hBN exhibits zero-field Chern insulating phases and lacks superconductivity. Here we use scanning tunneling microscopy and spectroscopy (STM/STS) to observe gapped phases at partial fillings of the flat bands of MATBG in a new intermediate regime of sublattice polarization, observed when MATBG is only partially aligned ($\theta_{Gr-hBN}$ $\approx$ 1.65$^\circ$) to the underlying hBN substrate. Under this condition, MATBG hosts not only phenomena that naturally interpolate between the two sublattice potential limits, but also unexpected gapped phases absent in either of these limits. At charge neutrality, we observe an insulating phase with a small energy gap ($\Delta$ < 5 meV) likely related to weak sublattice symmetry breaking from the hBN substrate. In addition, we observe new gapped phases near fractional fillings $\nu$ = $\pm 1/3$ and $\nu$ = $\pm 1/6$, which have not been previously observed in MATBG. Importantly, energy-resolved STS unambiguously identifies these fractional filling states to be of single-particle origin, possibly a result of the super-superlattice formed by two moir\'e superlattices. Our observations emphasize the power of STS in distinguishing single-particle gapped phases from many-body gapped phases in situations that could be easily confused in electrical transport measurements.Comment: 4 figure