Reliability-based Fracture Analysis for Shallow Shell Structure with the Dual Boundary Element Method

Reliability analysis has gained prominence as a stochastic approach to incorporate uncertainties in structural analysis. This study presents a novel methodology for evaluating the sensitivity of the crack tip stress intensity factor in a shallow shell structure. The work focuses on the reliability analysis of a shallow shell structure containing a crack originating from the corner of a fuselage window. The analysis incorporates uncertainties in both geometrical and loading parameters. The sensitivity of the crack tip stress intensity factors with respect to the considered uncertainties is determined. The Implicit Differentiation Method (IDM)-based First-Order Reliability Method (FORM) is utilized, and the results are compared to the results obtained from Monte Carlo Simulation (MCS), with a maximum difference of 2.99%. The reliability analysis aids in determining an appropriate inspection crack size that satisfies safety requirements, consequently facilitating the selection of the corresponding inspection technique

Superadditivity in Trade-Off Capacities of Quantum Channels

© 1963-2012 IEEE. In this paper, we investigate the additivity phenomenon in the quantum dynamic capacity region of a quantum channel for trading the resources of classical communication, quantum communication, and entanglement. Understanding such an additivity property is important if we want to optimally use a quantum channel for general communication purposes. However, in a lot of cases, the channel one will be using only has an additive single or double resource capacity region, and it is largely unknown if this could lead to a strictly superadditive double or triple resource capacity region, respectively. For example, if a channel has additive classical and quantum capacities, can the classical-quantum capacity region be strictly superadditive? In this paper, we answer such questions affirmatively. We give proof-of-principle requirements for these channels to exist. In most cases, we can provide an explicit construction of these quantum channels. The existence of these superadditive phenomena is surprising in contrast to the result that the additivity of both classical-entanglement and classical-quantum capacity regions imply the additivity of the triple resource capacity region for a given channel

Statistical Inference of Equivalent Initial Flaw Size Distribution for Fatigue Analysis of an Anisotropic Material

A novel methodology for the fatigue life uncertainty quantification of anisotropic structures is presented in this work. The concept of the equivalent initial flaw size distribution (EIFSD) is employed to overcome the difficulties in small cracks detection and fatigue prediction. This EIFSD concept is combined with the dual boundary element method (DBEM) to provide an efficient methodology for modelling the fatigue crack growth. Bayesian inference is used to infer the EIFSD based on inspection data from the routine maintenance of the structure, simulated with the DBEM. A large amount of DBEM simulations were required for the Bayesian inference. Therefore, surrogate models are used as part of the inference to further improve computational efficiency. A numerical example featuring an anisotropic plate is investigated for demonstrating the proposed methodology. When considering a low level of uncertainty in the crack propagation parameters, an error of 0.12% was found between the estimated fatigue life obtained using the proposed method compared to actual fatigue life, and only 0.35% error when considering high level of uncertainty. The application of the estimated fatigue life can be used to determine an appropriate inspection interval for aircraft maintenance

Implicit differentiation-based reliability analysis for shallow shell structures with the Boundary Element Method

A novel methodology for evaluating the response sensitivities of shallow shell structures using the Boundary Element Method (BEM) is presented in this work. The implicit derivatives of the BEM formulations for shallow shell structures, with respect to the geometrical variables, such as curvature and thickness, have been derived for the first time and incorporated into an Implicit Differentiation Method (IDM). The IDM is employed in conjunction with the First Order Reliability Method (FORM) to evaluate the reliability of shallow shell structures. The accuracy of the IDM formulation is first validated against an analytical solution, with results showing a maximum difference of only 2.61%. The IDM was later validated against the Finite Difference Method (FDM), with results showing a maximum difference of only 0.11%. The IDM was also found to be significantly more efficient than the FDM, requiring 35% less CPU time when calculating sensitivities. This is further compounded by the fact that, unlike the FDM, the IDM does not require a step size. A numerical example featuring a circular shallow shell is used to demonstrate the application of the IDM-based FORM for assessing structural reliability. The uncertainty in curvature is set as a variable for the purpose of investigating its impact on reliability. The results of the reliability index obtained from the IDM-FORM are compared to the results obtained from FDM-FORM and were found to be very similar. An analysis of sensitivity is conducted to identify the most significant variables affecting reliability. It is found that uncertainties in curvature, thickness, and applied pressure distribution parameters have the largest impact on structural reliability. To demonstrate how the IDM could be used in practice, it was employed as gradient-based optimisation procedure featuring shallow-shell structures. The IDM was found to be a very efficient and accurate alternative to existing methods for calculating structural response sensitivities

Human Gyrovirus Apoptin shows a similar subcellular distribution pattern and apoptosis induction as the chicken anaemia virus derived VP3/Apoptin

The chicken anaemia virus-derived protein Apoptin/VP3 (CAV-Apoptin) has the important ability to induce tumour-selective apoptosis in a variety of human cancer cells. Recently the first human Gyrovirus (HGyV) was isolated from a human skin swab. It shows significant structural and organisational resemblance to CAV and encodes a homologue of CAV-Apoptin/VP3. Using overlapping primers we constructed a synthetic human Gyrovirus Apoptin (HGyV-Apoptin) fused to green fluorescent protein in order to compare its apoptotic function in various human cancer cell lines to CAV-Apoptin. HGyV-Apoptin displayed a similar subcellular expression pattern as observed for CAV-Apoptin, marked by translocation to the nucleus of cancer cells, although it is predominantly located in the cytosol of normal human cells. Furthermore, expression of either HGyV-Apoptin or CAV-Apoptin in several cancer cell lines triggered apoptosis at comparable levels. These findings indicate a potential anti-cancer role for HGyV-Apoptin

Evolutionary Computation, Optimization and Learning Algorithms for Data Science

A large number of engineering, science and computational problems have yet to be solved in a computationally efficient way. One of the emerging challenges is how evolving technologies grow towards autonomy and intelligent decision making. This leads to collection of large amounts of data from various sensing and measurement technologies, e.g., cameras, smart phones, health sensors, smart electricity meters, and environment sensors. Hence, it is imperative to develop efficient algorithms for generation, analysis, classification, and illustration of data. Meanwhile, data is structured purposefully through different representations, such as large-scale networks and graphs. We focus on data science as a crucial area, specifically focusing on a curse of dimensionality (CoD) which is due to the large amount of generated/sensed/collected data. This motivates researchers to think about optimization and to apply nature-inspired algorithms, such as evolutionary algorithms (EAs) to solve optimization problems. Although these algorithms look un-deterministic, they are robust enough to reach an optimal solution. Researchers do not adopt evolutionary algorithms unless they face a problem which is suffering from placement in local optimal solution, rather than global optimal solution. In this chapter, we first develop a clear and formal definition of the CoD problem, next we focus on feature extraction techniques and categories, then we provide a general overview of meta-heuristic algorithms, its terminology, and desirable properties of evolutionary algorithms

Cholesterol and the risk of grade-specific prostate cancer incidence: evidence from two large prospective cohort studies with up to 37 years' follow up

<b>Background</b> High cholesterol may be a modifiable risk factor for prostate cancer but results have been inconsistent and subject to potential "reverse causality" where undetected disease modifies cholesterol prior to diagnosis.<p></p> <b>Methods</b> We conducted a prospective cohort study of 12,926 men who were enrolled in the Midspan studies between 1970 and 1976 and followed up to 31st December 2007. We used Cox-Proportional Hazards Models to evaluate the association between baseline plasma cholesterol and Gleason grade-specific prostate cancer incidence. We excluded cancers detected within at least 5 years of cholesterol assay.<p></p> <b>Results</b> 650 men developed prostate cancer in up to 37 years' follow-up. Baseline plasma cholesterol was positively associated with hazard of high grade (Gleason score[greater than or equal to]8) prostate cancer incidence (n=119). The association was greatest among men in the 4th highest quintile for cholesterol, 6.1 to <6.69 mmol/l, Hazard Ratio 2.28, 95% CI 1.27 to 4.10, compared with the baseline of <5.05 mmol/l. This association remained significant after adjustment for body mass index, smoking and socioeconomic status.<p></p> <b>Conclusions</b> Men with higher cholesterol are at greater risk of developing high-grade prostate cancer but not overall risk of prostate cancer. Interventions to minimise metabolic risk factors may have a role in reducing incidence of aggressive prostate cancer

A monolithic integrated photonic microwave filter

[EN] Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.The authors acknowledge financial support from the Spanish Centro para el Desarrollo Tecnologico Industrial (CDTI) through the NEOTEC start-up programme, the European Commission through the 7th Research Framework Programme project, Photonic Advanced Research and Development for Integrated Generic Manufacturing (FP7-PARADIGM), the Generalitat Valenciana through the Programa para grupos de Investigacion de Excelencia (PROMETEO) project code 2013/012, the Spanish Ministerio de Economia y Comercio (MINECO) via project TEC2013-42332-P, PIF4ESP, and the Unwersitat Politecnica de Valencia (UPVOV) through projects 10-3E-492 and 08-3E-008 funded by the Fondos Europeos de Desarrollo Regional (FEDER). J.S. Fandino acknowledges financial support from Formacion de Profesorado Universitario (FPU) grant AP2010-1595.Sanchez Fandiño, JA.; Muñoz Muñoz, P.; Doménech Gómez, JD.; Capmany Francoy, J. (2017). A monolithic integrated photonic microwave filter. Nature Photonics. 11(2):124-129. https://doi.org/10.1038/NPHOTON.2016.233S124129112Novak, D. et al. Radio-over-fiber technologies for emerging wireless systems. IEEE J. Quantum Electron. 52, 1–11 (2016).Waterhouse, R. & Novak, D. Realizing 5G: microwave photonics for 5G mobile wireless systems. IEEE Microw. Mag. 16, 84–92 (2015).Won, R. Microwave photonics shines. Nat. Photon. 5, 736 (2011).Capmany, J. & Novak, D. Microwave photonics combines two worlds. Nat. Photon. 1, 319–330 (2007).Yao, J. Microwave photonics. J. Lightw. Technol. 27, 314–335 (2009).Andrews, J. G. et al. What will 5G be? IEEE J. Sel. Areas Commun. 32, 1065–1082 (2014).Gosh, A., et al. Millimetre-wave enhanced local area systems: a high-data-rate approach for future wireless networks. IEEE J. Sel. Areas Commun. 32, 1152–1163 (2014).Marpaung, D. et al. Integrated microwave photonics. Laser Photon. Rev. 7, 506–538 (2013).Iezekiel, S., Burla, M., Klamkin, J., Marpaung, D. & Capmany, J. RF engineering meets optoelectronics: progress in integrated microwave photonics. IEEE Microw. Mag. 16, 28–45 (2015).Mitchell, J. E. Integrated wireless backhaul over optical access networks. J. Lightw. Technol. 32, 3373–3382 (2014).Liu, C., Wang, J., Cheng, L., Zhu, M. & Chang, G.-K. Key microwave-photonics technologies for next-generation cloud-based radio access networks. J. Lightw. Technol. 32, 3452–3460 (2014).Norberg, E. J., Guzzon, R. S., Parker, J. S., Johansson, L. A. & Coldren, L. A. Programmable photonic microwave filters monolithically integrated in InP/InGaAsP. J. Lightw. Technol. 29, 1611–1619 (2011).Guzzon, R., Norberg, E., Parker, J., Johansson, L. & Coldren, L. Integrated InP–InGaAsP tuneable coupled ring optical bandpass filters with zero insertion loss. Opt. Express 19, 7816–7826 (2011).Fandiño, J. S. & Muñoz, P. Photonics-based microwave frequency measurement using a double-sideband suppressed-carrier modulation and an InP integrated ring-assisted Mach–Zehnder interferometer filter. Opt. Lett. 38, 4316–4319 (2013).Burla, M. et al. On-chip ultra-wideband microwave photonic phase shifter and true time delay line based on a single phase-shifted waveguide Bragg grating. In IEEE International Topical Meeting on Microwave Photonics 92–95 (IEEE, 2013).Shi, W., Veerasubramanian, V., Patel, D. & Plant, D. Tuneable nanophotonic delay lines using linearly chirped contradirectioinal couplers with uniform Bragg gratings. Opt. Lett. 39, 701–703 (2014).Guan, B. et al. CMOS compatible reconfigurable silicon photonic lattice filters using cascaded unit cells for RF-photonic processing. IEEE J. Sel. Top. Quantum Electron. 20, 359–368 (2014).Khan, M. H. et al. Ultrabroad-bandwidth arbitrary radiofrequency waveform generation with a silicon photonic chip-based spectral shaper. Nat. Photon. 4, 117–122 (2010).Pagani, M. et al. Instantaneous frequency measurement system using four-wave mixing in an ultra-compact long silicon waveguide. In Proc. 41st European Conf. on Optical Communication (ECOC) 1–3 (IEEE, 2015).Khilo, A. et al. Photonic ADC: overcoming the bottleneck of electronic jitter. Opt. Express 20, 4454–4469 (2012).Wang, J. et al. Reconfigurable radio-frequency arbitrary waveforms synthesized in a silicon photonic chip. Nat. Commun. 6, 5957 (2015).Marpaung, D. et al. Si3N4 ring resonator-based microwave photonic notch filter with an ultrahigh peak rejection. Opt. Express 21, 23286–23294 (2013).Zhuang, L. et al. Ring resonator-based on-chip modulation transformer for high-performance phase-modulated microwave photonic links. Opt. Express 21, 25999–26013 (2013).Marpaung, D., Chevalier, L., Burla, M. & Roeloffzen, C. Impulse radio ultrawideband pulse shaper based on a programmable photonic chip frequency discriminator. Opt. Express 19, 24838–24848 (2011).Marpaung, D. On-chip photonic-assisted instantaneous microwave frequency measurement system. IEEE Photon. Technol. Lett. 25, 837–840 (2013).Burla, M. et al. On-chip CMOS compatible reconfigurable optical delay line with separate carrier tuning for microwave photonic signal processing. Opt. Express 19, 21475–21484 (2011).Tan, K. et al. Photonic-chip-based all-optical ultra-wideband pulse generation via XPM and birefringence in a chalcogenide waveguide. Opt. Express 21, 2003–2011 (2013).Pagani, M. et al. Tuneable wideband microwave photonic phase shifter using on-chip stimulated Brillouin scattering. Opt. Express 22, 28810–28818 (2014).Pérez, D., Gasulla, I. & Capmany, J. Software-defined reconfigurable microwave photonics processor. Opt. Express 23, 14640–14654 (2015).Capmany, J., Gasulla, I. & Pérez, D. Microwave photonics: the programmable processor. Nat. Photon. 10, 6–8 (2016).Zhuang, L., Roeloffzen, C. G. H., Hoekman, M., Boller, K.-J. & Lowery, A. J. Programmable photonic signal processor chip for radiofrequency applications. Optica 2, 854–859 (2015).Roeloffzen, C. G. et al. Silicon nitride microwave photonic circuits. Opt. Express 21, 22937–22961 (2013).Liu, W. et al. A fully reconfigurable photonic integrated signal processor. Nat. Photon. 10, 190–195 (2016).Madsen, C. K. & Zhao, J. H. Optical Filter Design and Analysis: A Signal Processing Approach (Wiley, 1999).Román, J., Frankel, M. Y. & Esman, R. D. Spectral characterization of fiber gratings with high resolution. Opt. Lett. 23, 939–941 (1998).Hernández, R., Loayssa, A. & Benito, D. Optical vector network analysis based on single-sideband modulation. Opt. Eng. 43, 2418–2421 (2004).Jinguji, K. & Oguma, M. Optical half-band filters. J. Lightw. Technol. 18, 252–259 (2000).Madsen, C. K. Efficient architectures for exactly realizing optical filters with optimum bandpass designs. IEEE Photon. Technol. Lett. 10, 1136–1138 (1998).Madsen, C. K. General IIR optical filter design for WDM applications using all-pass filters. J. Lightw. Technol. 18, 860–868 (2000).Smit, M. K. et al. An introduction to InP-based generic integration technology. Semicond. Sci. Technol. 29, 083001 (2014).Besse, P. A., Gini, E., Bachmann, M. & Melchior, H. New 2×2 and 1×3 multimode interference couplers with free selection of power splitting ratios. J. Lightw. Technol. 14, 2286–2293 (1996).Pérez, D. et al. Figures of merit for self-beating filtered microwave photonic systems. Opt. Express 24, 10087–10102 (2016).Zhuang, L. et al. Novel low-loss waveguide delay lines using Vernier ring resonators for on-chip multi-λ microwave photonic signal processors. Laser Photon. Rev. 7, 994–1002 (2013)

Spatio-temporal Models of Lymphangiogenesis in Wound Healing

Several studies suggest that one possible cause of impaired wound healing is failed or insufficient lymphangiogenesis, that is the formation of new lymphatic capillaries. Although many mathematical models have been developed to describe the formation of blood capillaries (angiogenesis), very few have been proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a markedly different process from angiogenesis, occurring at different times and in response to different chemical stimuli. Two main hypotheses have been proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic endothelial cells first pool in the wound region following the lymph flow and then, once sufficiently populated, start to form a network. Here we present two PDE models describing lymphangiogenesis according to these two different hypotheses. Further, we include the effect of advection due to interstitial flow and lymph flow coming from open capillaries. The variables represent different cell densities and growth factor concentrations, and where possible the parameters are estimated from biological data. The models are then solved numerically and the results are compared with the available biological literature.Comment: 29 pages, 9 Figures, 6 Tables (39 figure files in total