184 research outputs found
The Augmented Complex Kernel LMS
Recently, a unified framework for adaptive kernel based signal processing of
complex data was presented by the authors, which, besides offering techniques
to map the input data to complex Reproducing Kernel Hilbert Spaces, developed a
suitable Wirtinger-like Calculus for general Hilbert Spaces. In this short
paper, the extended Wirtinger's calculus is adopted to derive complex
kernel-based widely-linear estimation filters. Furthermore, we illuminate
several important characteristics of the widely linear filters. We show that,
although in many cases the gains from adopting widely linear estimation
filters, as alternatives to ordinary linear ones, are rudimentary, for the case
of kernel based widely linear filters significant performance improvements can
be obtained.Comment: manuscript submitted to IEE Transactions on Signal Processin
6 Access Methods and Query Processing Techniques
The performance of a database management system (DBMS) is fundamentally dependent on the access methods and query processing techniques available to the system. Traditionally, relational DBMSs have relied on well-known access methods, such as the ubiquitous B +-tree, hashing with chaining, and, in som
Effects of Long-Versus Short-Term Exposure to the Mediterranean Diet on Skin Microvascular Function and Quality of Life of Healthy Adults in Greece and the UK
The beneficial effects of the Mediterranean diet (MD) adherence in reducing cardiovascular disease (CVD) risk and improving CVD-related physiological indices have been well-documented. However, the exact MD adherence duration needed for these effects to occur is under-researched. The aim of the present, two-arm, two-site study clinical trial was to assess the effects of long- vs. short-term MD adherence on the skin microvascular circulation, and quality of life. Two groups were recruited, one being long-term MD adherers (>5 years; from Greece; control group), and one of the non-adherers (from the UK), with the latter participating in a four-week MD intervention (intervention group). Our main outcome was skin microvascular function assessed by cutaneous vascular conductance (CVC). Secondary outcomes included quality of life, dietary intake, blood pressure and lipidemic profile. At the end of the intervention, both groups had high MD adherence. For the intervention group, significantly improved post-intervention CVC values were noted concerning the initial peak phase (2.0 ± 0.6 vs. 2.8 ± 0.8; p 0.05). CVC values of the control group, were however higher at the plateau phase in comparison to the intervention group (intervention end; 3.8 ± 0.8 vs. 3.1 ± 1.2; p 0.05). As per QoL, the physical domain was improved post-intervention (13.7 ± 1.2 vs. 15.9 ± 1.2; p 0.05). No differences were observed in the lipidemic profile between groups, or between the baseline and final intervention phases. The findings indicate that although short-term MD adherence is effective in improving certain microvascular physiological properties and QoL domains, there is room for additional improvement, observed in long-term adherers. Our findings are important in the design of future, MD-based, lifestyle interventions, with the advisable durations differing between target groups
Analytical Estimation of the Electrostatic Field in Cylinder-Plane and Cylinder-Cylinder Electrode Configurations
This work presents analytical formulas for the estimation of the electrostatic field in cylinder-plane and cylinder-cylinder electrode configurations. Assuming a predefined potential difference between the electrodes and given their geometrical characteristics, these could be useful for the solution of numerous problems involving such electrode sets. Moreover, the voltage distribution around the electrodes is defined by providing equations either for the equipotentials at a given voltage ratio, or the exact estimation of the potential at any point in the surrounding space. Simplified expressions for critical engineering parameters such as the peak electric field and the field enhancement factor are also given
Unconventional Monetary Policies and the Macroeconomy:The Impact of the UK's QE2 and Funding for Lending Scheme
In this paper we assess the macroeconomic effects of two of the flagship unconventional monetary policies used by the Bank of England during the later stages of the global economic crisis: additional Quantitative Easing (QE) and the introduction of the Funding for Lending Scheme (FLS). We argue that these policies can be seen as complements, as QE effectively bypasses the banks by attempting to reduce risk-free yields directly in order to have a wider effect on asset prices, while FLS operates directly through banks by reducing their funding costs and increasing incentives to lend. We attempt to quantify the effects of these policies by estimating their impact on long-term interest rates and bank funding costs, respectively, and then tracing out their wider effects on the macroeconomy using simulations from a large Bayesian vector autoregression (VAR), which are cross-checked with a simpler Auto-regressive distributed lag (ARDL) approach. We find that the second round of the Bank's QE purchases during 2011-12 and the initial phase of the FLS each boosted GDP in the UK by around 0.5%-0.8%. Their effect on inflation was also broadly positive reaching around 0.6 pp, at its peak
Upper-lip laser frenectomy without infiltrated anaesthesia in a paediatric patient: a case report
Labial frenectomy is a common surgical procedure in the field of oral surgery. Labial frenectomy is a procedure usually done for orthodontic reasons. The role of laser surgery in the oral cavity is well established. The use of diode laser frenectomy without infiltrated anaesthesia is currently under investigation. Needle-less oral surgery, without infiltrated anaesthesia, is a novel situation in paediatrics with paramount importance
Fast Linear Programming through Transprecision Computing on Small and Sparse Data
A plethora of program analysis and optimization techniques rely on linear programming at their heart. However, such techniques are often considered too slow for production use. While today’s best solvers are optimized for complex problems with thousands of dimensions, linear programming, as used in compilers, is typically applied to small and seemingly trivial problems, but to many instances in a single compilation run. As a result, compilers do not benefit from decades of research on optimizing large-scale linear programming. We design a simplex solver targeted at compilers. A novel theory of transprecision computation applied from individual elements to full data-structures provides the computational foundation. By carefully combining it with optimized representations for small and sparse matrices and specialized small-coefficient algorithms, we (1) reduce memory traffic, (2) exploit wide vectors, and (3) use low-precision arithmetic units effectively. We evaluate our work by embedding our solver into a state-of-the-art integer set library and implement one essential operation, coalescing, on top of our transprecision solver. Our evaluation shows more than an order-of-magnitude speedup on the core simplex pivot operation and a mean speedup of 3.2x (vs. GMP) and 4.6x (vs. IMath) for the optimized coalescing operation. Our results demonstrate that our optimizations exploit the wide SIMD instructions of modern microarchitectures effectively. We expect our work to provide foundations for a future integer set library that uses transprecision arithmetic to accelerate compiler analyses.ISSN:2475-142
Analytical Estimation of the Electrostatic Field in Cylinder-Plane and Cylinder-Cylinder Electrode Configurations
<p><span lang="EN-US">This work presents analytical formulas for the estimation of the electrostatic field in cylinder-plane and cylinder-cylinder electrode configurations. Assuming a predefined potential difference between the electrodes and given their geometrical characteristics, these could be useful for the solution of numerous problems involving such electrode sets. Moreover, the voltage distribution around the electrodes is defined by providing equations either for the equipotentials at a given voltage ratio, or the exact estimation of the potential at any point in the surrounding space. Simplified expressions for critical engineering parameters such as the peak electric field and the field enhancement factor are also given.</span></p></jats:p
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