Realization of perfect reconstruction non-uniform filter banks via a tree structure

Obviously, a tree structure filter bank can be realized via a non-uniform filter bank, and perfect reconstruction is achieved if and only if each branch of the tree structure can provide perfect reconstruction. In this paper, the converse of this problem is studied. We show that a perfect reconstruction non-uniform filter bank with decimation ratio {2,4,4} can be realized via a tree structure and each branch of the tree structure achieves perfect reconstruction

Development of EM-CCD-based X-ray detector for synchrotron applications

A high speed, low noise camera system for crystallography and X-ray imaging applications is developed and successfully demonstrated. By coupling an electron-multiplying (EM)-CCD to a 3:1 fibre-optic taper and a CsI(Tl) scintillator, it was possible to detect hard X-rays. This novel approach to hard X-ray imaging takes advantage of sub-electron equivalent readout noise performance at high pixel readout frequencies of EM-CCD detectors with the increase in the imaging area that is offered through the use of a fibre-optic taper. Compared with the industry state of the art, based on CCD camera systems, a high frame rate for a full-frame readout (50 ms) and a lower readout noise (<1 electron root mean square) across a range of X-ray energies (6–18 keV) were achieved

Image lag optimisation in a 4T CMOS image sensor for the JANUS camera on ESA's JUICE mission to Jupiter

The CIS115, the imager selected for the JANUS camera on ESA’s JUICE mission to Jupiter, is a Four Transistor (4T) CMOS Image Sensor (CIS) fabricated in a 0.18 µm process. 4T CIS (like the CIS115) transfer photo generated charge collected in the pinned photodiode (PPD) to the sense node (SN) through the Transfer Gate (TG). These regions are held at different potentials and charge is transferred from the potential well under PPD to the potential well under the FD through a voltage pulse applied to the TG. Incomplete transfer of this charge can result in image lag, where signal in previous frames can manifest itself in subsequent frames, often appearing as ghosted images in successive readouts. This can seriously affect image quality in scientific instruments and must be minimised. This is important in the JANUS camera, where image quality is essential to help JUICE meet its scientific objectives. This paper presents two techniques to minimise image lag within the CIS115. An analysis of the optimal voltage for the transfer gate voltage is detailed where optimisation of this TG “ON” voltage has shown to minimise image lag in both an engineering model and gamma and proton irradiated devices. Secondly, a new readout method of the CIS115 is described, where following standard image integration, the PPD is biased to the reset voltage level (VRESET) through the transfer gate to empty charge on the PPD and has shown to reduce image lag in the CIS115

REPAIR: Hard-error recovery via re-execution

Processor reliability at upcoming technology nodes presents significant challenges to designers from increased manufacturing variability, parametric variation and transistor wear-out leading to permanent faults. We present a design to tolerate this impact at the microarchitectural level—a chip with n cores together with one or more shared instruction re-execution units (IRUs). Instructions using a faulty component are identified and re-executed on an IRU. This design incurs no slowdown in the absence of errors and allows continued operation of all n cores after multiple hard errors on one or all cores in the structures protected by our scheme. Experiments show that a single-core chip experiences only a 23% slowdown with 1 error, rising to 43% in the presence of 5 errors. In a 4-core scenario with 4 errors on every core and a shared IRU, REPAIR enables performance of 0.68× of a fully functioning system.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) through grants EP/K026399/1 and EP/J016284/1. Experiments used the Darwin Supercomputer of the University of Cambridge High Performance Computing Service (http://www.hpc.cam.ac.uk/) funded by the Higher Education Funding Council for England and the Science and Technology Facilities Council.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/DFT.2015.731513

The lack of paid sick leave as a barrier to cancer screening and medical care-seeking: results from the National Health Interview Survey

BACKGROUND: Preventive health care services, such as cancer screening can be particularly vulnerable to a lack of paid leave from work since care is not being sought for illness or symptoms. We first describe the prevalence of paid sick leave by broad occupational categories and then examine the association between access to paid sick leave and cancer testing and medical care-seeking in the U.S. workforce. METHODS: Data from the 2008 National Health Interview survey were analyzed by using paid sick leave status and other health-related factors to describe the proportion of U.S. workers undergoing mammography, Pap testing, endoscopy, fecal occult blood test (FOBT), and medical-care seeking. RESULTS: More than 48 million individuals (38%) in an estimated U.S. working population of 127 million did not have paid sick leave in 2008. The percentage of workers who underwent mammography, Pap test, endoscopy at recommended intervals, had seen a doctor during the previous 12 months or had at least one visit to a health care provider during the previous 12 months was significantly higher among those with paid sick leave compared with those without sick leave after controlling for sociodemographic and health-care-related factors. CONCLUSIONS: Lack of paid sick leave appears to be a potential barrier to obtaining preventive medical care and is a societal benefit that is potentially amenable to change

Second-order perturbation theory-based digital predistortion for fiber nonlinearity compensation

The first-order (FO) perturbation theory-based nonlinearity compensation (PB-NLC) technique has been widely investigated to combat the detrimental effects of the intra-channel Kerr nonlinearity in polarization-multiplexed (Pol-Mux) optical fiber communication systems. However, the NLC performance of the FO-PB-NLC technique is significantly limited in highly nonlinear regimes of the Pol-Mux long-haul optical transmission systems. In this paper, we extend the FO theory to second-order (SO) to improve the NLC performance. This technique is referred to as the SO-PB-NLC. A detailed theoretical analysis is performed to derive the SO perturbative field for a Pol-Mux optical transmission system. Following that, we investigate a few simplifying assumptions to reduce the implementation complexity of the SO-PB-NLC technique. The numerical simulations for a single-channel system show that the SO-PB-NLC technique provides an improved bit-error-rate performance and increases the transmission reach, in comparison with the FO-PB-NLC technique. The complexity analysis demonstrates that the proposed SO-PB-NLC technique has a reduced computational complexity when compared to the digital back-propagation with one step per span

Impact of Medical Education Trend in Community Development

Problem-based learning has been described as one of the most significant developments in medical education. The trend of medical education plays a vital role in determining the success of universal health coverage in India.&nbsp; The motto of health education is community-based training, where students are placed in the community and learn by delivering the care using the existing health services

Improving radiation hardness in space-based Charge-Coupled Devices through the narrowing of the charge transfer channel

Charge-Coupled Devices (CCDs) have been the detector of choice for imaging and spectroscopy in space missions for several decades, such as those being used for the Euclid VIS instrument and baselined for the SMILE SXI. Despite the many positive properties of CCDs, such as the high quantum efficiency and low noise, when used in a space environment the detectors suffer damage from the often-harsh radiation environment. High energy particles can create defects in the silicon lattice which act to trap the signal electrons being transferred through the device, reducing the signal measured and effectively increasing the noise. We can reduce the impact of radiation on the devices through four key methods: increased radiation shielding, device design considerations, optimisation of operating conditions, and image correction. Here, we concentrate on device design operations, investigating the impact of narrowing the charge-transfer channel in the device with the aim of minimising the impact of traps during readout. Previous studies for the Euclid VIS instrument considered two devices, the e2v CCD204 and CCD273, the serial register of the former having a 50 μm channel and the latter having a 20 μm channel. The reduction in channel width was previously modelled to give an approximate 1.6× reduction in charge storage volume, verified experimentally to have a reduction in charge transfer inefficiency of 1.7×. The methods used to simulate the reduction approximated the charge cloud to a sharp-edged volume within which the probability of capture by traps was 100%. For high signals and slow readout speeds, this is a reasonable approximation. However, for low signals and higher readout speeds, the approximation falls short. Here we discuss a new method of simulating and calculating charge storage variations with device design changes, considering the absolute probability of capture across the pixel, bringing validity to all signal sizes and readout speeds. Using this method, we can optimise the device design to suffer minimum impact from radiation damage effects, here using detector development for the SMILE mission to demonstrate the process

Affine arithmetic-based methodology for energy hub operation-scheduling in the presence of data uncertainty

In this study, the role of self-validated computing for solving the energy hub-scheduling problem in the presence of multiple and heterogeneous sources of data uncertainties is explored and a new solution paradigm based on affine arithmetic is conceptualised. The benefits deriving from the application of this methodology are analysed in details, and several numerical results are presented and discussed