The wavelet-NARMAX representation : a hybrid model structure combining polynomial models with multiresolution wavelet decompositions

A new hybrid model structure combing polynomial models with multiresolution wavelet decompositions is introduced for nonlinear system identification. Polynomial models play an important role in approximation theory, and have been extensively used in linear and nonlinear system identification. Wavelet decompositions, in which the basis functions have the property of localization in both time and frequency, outperform many other approximation schemes and offer a flexible solution for approximating arbitrary functions. Although wavelet representations can approximate even severe nonlinearities in a given signal very well, the advantage of these representations can be lost when wavelets are used to capture linear or low-order nonlinear behaviour in a signal. In order to sufficiently utilise the global property of polynomials and the local property of wavelet representations simultaneously, in this study polynomial models and wavelet decompositions are combined together in a parallel structure to represent nonlinear input-output systems. As a special form of the NARMAX model, this hybrid model structure will be referred to as the WAvelet-NARMAX model, or simply WANARMAX. Generally, such a WANARMAX representation for an input-output system might involve a large number of basis functions and therefore a great number of model terms. Experience reveals that only a small number of these model terms are significant to the system output. A new fast orthogonal least squares algorithm, called the matching pursuit orthogonal least squares (MPOLS) algorithm, is also introduced in this study to determine which terms should be included in the final model

Comparing Sales Strategies Using the Markov Chain Relationship Model

In this paper, the author applied the concept of the Markov chain and divided sales procedures into several indexes and states; use the state index for connecting success in sales and customer relations into Pfeifer’s method, establish a mathematical model, and demonstrate its result. In order to increase profits and decrease the cost of sales for the company, we further classify customers and propose different sale strategies. Case study and analysis are provided to elaborate the approach and its contribution to sales and CRM (customer relationship management) strategy

Late-onset secondary pigmentary glaucoma following foldable intraocular lenses implantation in the ciliary sulcus: a long-term follow-up study

BACKGROUND: To review the long-term outcomes of eyes with secondary pigmentary glaucoma associated with the implantation of foldable intraocular lenses (IOL) in the ciliary sulcus. METHODS: The study retrospectively reviewed a series of cases who developed secondary pigmentary glaucoma after cataract operations. Data were collected from cases that were referred between 2002 and 2011. RESULTS: Ten eyes of 10 patients who developed secondary pigmentary glaucoma after foldable IOLs implantation in the sulcus were included in this study. Intraocular pressure (IOP) elevation was present in 2 eyes (20%) within the first 2 weeks following the initial cataract operation. The onset of glaucoma was delayed in the other 8 eyes (80%); the average onset time in these eyes was 21.9 ± 17.1 months after the initial cataract operation. Six eyes (60%) received surgical treatment because of large fluctuations and poor control of IOPs. Only 3 eyes (30%) achieved final visual acuities better than 20/40. CONCLUSION: Secondary pigmentary glaucoma accompanying the implantation of a foldable IOL in the ciliary sulcus may present as acute IOP elevation during the early postoperative period or, more commonly, late onset of IOP elevation accompanied by advanced glaucomatous optic nerve damage. Despite treatment, the visual prognosis for these patients can be poor. Placing a foldable IOL in the ciliary sulcus could pose a threat to the vision of the patients and long-term follow-up of IOP in these patients is necessary

A General Design Rule to Manipulate Photocarrier Transport Path in Solar Cells and Its Realization by the Plasmonic-Electrical Effect

It is well known that transport paths of photocarriers (electrons and holes) before collected by electrodes strongly affect bulk recombination and thus electrical properties of solar cells, including open-circuit voltage and fill factor. For boosting device performance, a general design rule, tailored to arbitrary electron to hole mobility ratio, is proposed to decide the transport paths of photocarriers. Due to a unique ability to localize and concentrate light, plasmonics is explored to manipulate photocarrier transport through spatially redistributing light absorption at the active layer of devices. Without changing the active materials, we conceive a plasmonic-electrical concept, which tunes electrical properties of solar cells via the plasmon-modified optical field distribution, to realize the design rule. Incorporating spectrally and spatially configurable metallic nanostructures, thin-film solar cells are theoretically modelled and experimentally fabricated to validate the design rule and verify the plasmonic-tunable electrical properties. The general design rule, together with the plasmonic-electrical effect, contributes to the evolution of emerging photovoltaics.published_or_final_versio

Preventing failure of the anchoring system in underground coal mines

Cable bolts are commonly used as anchoring element in many underground mines. Reports on the premature failure of cable bolts in underground coal mines due to stress corrosion cracking (SCC) have been increasing in the past two decades. The previous studies found that the diffusion of atomic hydrogen into steel causes the SCC in cable bolts, which is known as hydrogen-induced stress corrosion cracking (HISCC). While the research on the mechanism of the HISCC in underground mines needs to be continued, it is essential to develop prevention measures to avoid such a failure. In this study, a variety of prevention measures that claim to prevent corrosion of steel were examined. Specifically, barrier coating, i.e., polymer, epoxy coating, as well as the sacrificial coating, i.e., hot-dip galvanising, methods were tested. Testing specimens were made by inserting loading pins between locked cable bolt king wires (coated) to simulate the in-situ stress condition. Cable bolt specimens were then fully immersed into a hydrogen sulphide solution to determine their resistance against HISCC. The test results showed that all the coatings had delayed the failure in varying degrees, but very few have significantly extended the time to fracturing. The polymer and epoxy coatings have become breached during the testing, and the failure occurred shortly after. The galvanised coating was dissolved in the testing solution and again allowed access of the solution to the steel surface, and subsequently resulted in failure. This indicates that these coatings can be potentially applied to prevent SCC failure; however, their impacts on the performance of bolts, such as their bonding with grout and bolt, still need to be considered

Oral tolerance to cancer can be abrogated by T regulatory cell inhibition

Oral administration of tumour cells induces an immune hypo-responsiveness known as oral tolerance. We have previously shown that oral tolerance to a cancer is tumour antigen specific, non-cross-reactive and confers a tumour growth advantage. We investigated the utilisation of regulatory T cell (Treg) depletion on oral tolerance to a cancer and its ability to control tumour growth. Balb/C mice were gavage fed homogenised tumour tissue – JBS fibrosarcoma (to induce oral tolerance to a cancer), or PBS as control. Growth of subcutaneous JBS tumours were measured; splenic tissue excised and flow cytometry used to quantify and compare systemic Tregs and T effector (Teff) cell populations. Prior to and/or following tumour feeding, mice were intraperitoneally administered anti-CD25, to inactivate systemic Tregs, or given isotype antibody as a control. Mice which were orally tolerised prior to subcutaneous tumour induction, displayed significantly higher systemic Treg levels (14% vs 6%) and faster tumour growth rates than controls (p<0.05). Complete regression of tumours were only seen after Treg inactivation and occurred in all groups - this was not inhibited by tumour feeding. The cure rates for Treg inactivation were 60% during tolerisation, 75% during tumour growth and 100% during inactivation for both tolerisation and tumour growth. Depletion of Tregs gave rise to an increased number of Teff cells. Treg depletion post-tolerisation and post-tumour induction led to the complete regression of all tumours on tumour bearing mice. Oral administration of tumour tissue, confers a tumour growth advantage and is accompanied by an increase in systemic Treg levels. The administration of anti-CD25 Ab decreased Treg numbers and caused an increase in Teffs. Most notably Treg cell inhibition overcame established oral tolerance with consequent tumor regression, especially relevant to foregut cancers where oral tolerance is likely to be induced by the shedding of tumour tissue into the gut

Unusual Formation of Point-Defect Complexes in the Ultrawide-Band-Gap Semiconductor β-Ga2 O3

Understanding the unique properties of ultra-wide band gap semiconductors requires detailed information about the exact nature of point defects and their role in determining the properties. Here, we report the first direct microscopic observation of an unusual formation of point defect complexes within the atomic-scale structure of β-Ga2O3 using high resolution scanning transmission electron microscopy (STEM). Each complex involves one cation interstitial atom paired with two cation vacancies. These divacancy-interstitial complexes correlate directly with structures obtained by density functional theory, which predicts them to be compensating acceptors in β-Ga2O3. This prediction is confirmed by a comparison between STEM data and deep level optical spectroscopy results, which reveals that these complexes correspond to a deep trap within the band gap, and that the development of the complexes is facilitated by Sn doping through increased vacancy concentration. These findings provide new insight on this emerging material's unique response to the incorporation of impurities that can critically influence their properties

On Feedback Vertex Set: New Measure and New Structures

We present a new parameterized algorithm for the {feedback vertex set} problem ({\sc fvs}) on undirected graphs. We approach the problem by considering a variation of it, the {disjoint feedback vertex set} problem ({\sc disjoint-fvs}), which finds a feedback vertex set of size $k$ that has no overlap with a given feedback vertex set $F$ of the graph $G$. We develop an improved kernelization algorithm for {\sc disjoint-fvs} and show that {\sc disjoint-fvs} can be solved in polynomial time when all vertices in $G \setminus F$ have degrees upper bounded by three. We then propose a new branch-and-search process on {\sc disjoint-fvs}, and introduce a new branch-and-search measure. The process effectively reduces a given graph to a graph on which {\sc disjoint-fvs} becomes polynomial-time solvable, and the new measure more accurately evaluates the efficiency of the process. These algorithmic and combinatorial studies enable us to develop an $O^*(3.83^k)$-time parameterized algorithm for the general {\sc fvs} problem, improving all previous algorithms for the problem.Comment: Final version, to appear in Algorithmic

catena-poly[di-μ(2)-chloro(1,10-phenanthroline)cadmium(II)]

The crystal structure of the 1/1 adduct of cadmium dichloride with 1,10-phenanthroline, [CdCl2(C12H8N2)](n), is based on an infinite chain of Cd2Cl2 parallelograms sharing their Cd corners. The chain propagates in a zigzag manner along the c axis of the monoclinic unit cell. The Cd atom and the phenanthroline molecule both lie on special positions of 2 symmetry

Stress corrosion cracking of cable bolts in tunnels: An in-situ testing approach

Premature failure of cable bolts in underground tunnels is a major concern for the mining and civil industries. The unexpected failure of cable bolts in tunnels can threaten the safety of excavation operations and cause subnational economic losses. In this study, an in-situ testing method was developed to identify the cause of failure in the environment where the cable bolts are installed. The testing was conducted in two underground mine tunnels in Australia. The coupon made from non-galvanised and galvanised cable bolt wires with multiple stressed sections were installed in the tunnel roof, allowing direct exposure of coupons to different rock strata environments. The coupons were retrieved from the tunnels after almost ten months and analysed for corrosion. Results from both tunnels showed the occurrence of stress corrosion cracking (SCC) in both non-galvanised and galvanised coupons. The cracking predominantly occurred in the sections exposed to claystone layers. The framework developed in this study can be applied to different regions of any underground spaces to assess the propensity of the environment to cause premature reinforcement failure