Some results on two-sided LIL behavior

Let {X,X_n;n\geq 1} be a sequence of i.i.d. mean-zero random variables, and let S_n=\sum_{i=1}^nX_i,n\geq 1. We establish necessary and sufficient conditions for having with probability 1, 0<lim sup_{n\to \infty}|S_n|/\sqrtnh(n)<\infty, where h is from a suitable subclass of the positive, nondecreasing slowly varying functions. Specializing our result to h(n)=(\log \log n)^p, where p>1 and to h(n)=(\log n)^r, r>0, we obtain analogues of the Hartman-Wintner LIL in the infinite variance case. Our proof is based on a general result dealing with LIL behavior of the normalized sums {S_n/c_n;n\ge 1}, where c_n is a sufficiently regular normalizing sequence.Comment: Published at http://dx.doi.org/10.1214/009117905000000198 in the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

Novel self-configurable current-mirror techniques for reducing current imbalance in parallel Light-Emitting Diode (LED) strings

Traditional current-mirror methods require one fixed current reference for controlling other current source or sources. In this paper, a new self-configurable current-mirror method that can dynamically determine the best current branch as the current reference in order to ensure good balance of all parallel current sources is proposed. The operating principle involves a dynamic and self-configurable transistor-based current-balancing circuit that can be operated in saturation or linear mode. In either operating mode, good current balance or sharing among all parallel-connected current sources can be guaranteed. The novel current-balancing circuit does not require a separate power supply for powering their control circuits. The proposal is a modular one that can be expanded to any number of parallel current sources. Its principle has been successfully applied to current balancing of parallel LED strings. © 2011 IEEE.published_or_final_versio

MiR-29b negatively regulates cell cycle activity of human embryonic stem cell-derived cardiomyocytes

published_or_final_versionThe 16th Medical Resarch Conference (MRC), The University of Hong Kong, Hong Kong, China, 22 January 2011. In Hong Kong Medical Journal, 2011, v. 17, suppl. 1, p. 50, abstract no. 7

What is the impact of hotels on local economic development? Applying value chain analysis to individual businesses

The impact of mainstream tourist hotels on destination economies is clearly an important question for public policy-makers wishing to develop robust tourism policy. We adapt the methodology of value chain analysis to measure the local economic impact of a large, single tourism enterprise, to show how to generate commercially realistic data using the example of an analysis of a 1000 room all-inclusive resort in southern Turkey in partnership with TUI UK and Ireland. The data break down package revenues according to their beneficiaries and identifies areas for improvement. We further report and reflect on a 6-month evaluation of a tour operator-hotel partnership to deliver on a set of positive recommendations arising from the date to improve future impact

Eigenlogic: a Quantum View for Multiple-Valued and Fuzzy Systems

We propose a matrix model for two- and many-valued logic using families of observables in Hilbert space, the eigenvalues give the truth values of logical propositions where the atomic input proposition cases are represented by the respective eigenvectors. For binary logic using the truth values {0,1} logical observables are pairwise commuting projectors. For the truth values {+1,-1} the operator system is formally equivalent to that of a composite spin 1/2 system, the logical observables being isometries belonging to the Pauli group. Also in this approach fuzzy logic arises naturally when considering non-eigenvectors. The fuzzy membership function is obtained by the quantum mean value of the logical projector observable and turns out to be a probability measure in agreement with recent quantum cognition models. The analogy of many-valued logic with quantum angular momentum is then established. Logical observables for three-value logic are formulated as functions of the Lz observable of the orbital angular momentum l=1. The representative 3-valued 2-argument logical observables for the Min and Max connectives are explicitly obtained.Comment: 11 pages, 2 table

Probability representation and quantumness tests for qudits and two-mode light states

Using tomographic-probability representation of spin states, quantum behavior of qudits is examined. For a general j-qudit state we propose an explicit formula of quantumness witnetness whose negative average value is incompatible with classical statistical model. Probability representations of quantum and classical (2j+1)-level systems are compared within the framework of quantumness tests. Trough employing Jordan-Schwinger map the method is extended to check quantumness of two-mode light states.Comment: 5 pages, 2 figures, PDFLaTeX, Contribution to the 11th International Conference on Squeezed States and Uncertainty Relations (ICSSUR'09), June 22-26, 2009, Olomouc, Czech Republi

On Exceptional Times for generalized Fleming-Viot Processes with Mutations

If $\mathbf Y$ is a standard Fleming-Viot process with constant mutation rate (in the infinitely many sites model) then it is well known that for each $t>0$ the measure $\mathbf Y_t$ is purely atomic with infinitely many atoms. However, Schmuland proved that there is a critical value for the mutation rate under which almost surely there are exceptional times at which $\mathbf Y$ is a finite sum of weighted Dirac masses. In the present work we discuss the existence of such exceptional times for the generalized Fleming-Viot processes. In the case of Beta-Fleming-Viot processes with index $\alpha\in\,]1,2[$ we show that - irrespectively of the mutation rate and $\alpha$ - the number of atoms is almost surely always infinite. The proof combines a Pitman-Yor type representation with a disintegration formula, Lamperti's transformation for self-similar processes and covering results for Poisson point processes

A new noncontact method for the prediction of both internal thermal resistance and junction temperature of white light-emitting diodes

Although critical to the lifetime of LED, the junction temperature of LED cannot be measured easily. Based on the general photoelectrothermal theory for LED systems, the coefficient for the reduction of luminous efficacy with junction temperature is first related to the characteristic temperature of the LED. Then, a noncontact method for estimating the internal junction temperature T j and junction-case thermal resistance R jc of LED from the external power and luminous flux measurements is presented and verified practically. Since these external measurements can be obtained easily, the proposal provides a simple tool for checking T j in new LED system designs without using expensive or sophisticated thermal monitoring equipment for the LED junctions. The proposed method has been checked with measurements on LED devices from three different brands with both constant and nonconstant R jc. The theoretical predictions are found to be highly consistent with practical measurements. © 2011 IEEE.published_or_final_versio

MicroRNA-21 promotes survival but not functional maturation of human embryonic stem cell-derived cardiomyocytes (hESC-CMs)

published_or_final_versionThe 16th Medical Resarch Conference (MRC), The University of Hong Kong, Hong Kong, China, 22 January 2011. In Hong Kong Medical Journal, 2011, v. 17, suppl. 1, p. 35, abstract no. 5

Rubber Impact on 3D Textile Composites

A low velocity impact study of aircraft tire rubber on 3D textile-reinforced composite plates was performed experimentally and numerically. In contrast to regular unidirectional composite laminates, no delaminations occur in such a 3D textile composite. Yarn decohesions, matrix cracks and yarn ruptures have been identified as the major damage mechanisms under impact load. An increase in the number of 3D warp yarns is proposed to improve the impact damage resistance. The characteristic of a rubber impact is the high amount of elastic energy stored in the impactor during impact, which was more than 90% of the initial kinetic energy. This large geometrical deformation of the rubber during impact leads to a less localised loading of the target structure and poses great challenges for the numerical modelling. A hyperelastic Mooney-Rivlin constitutive law was used in Abaqus/Explicit based on a step-by-step validation with static rubber compression tests and low velocity impact tests on aluminium plates. Simulation models of the textile weave were developed on the meso- and macro-scale. The final correlation between impact simulation results on 3D textile-reinforced composite plates and impact test data was promising, highlighting the potential of such numerical simulation tools