A probabilistic alternative to regression suites

Automated regression suites are essential in developing large applications, while maintaining reasonable quality and timetables. The main argument against the automation of regression suites, in addition to the cost of creation and maintenance, is the observation that if you run the same test many times, it becomes increasingly less likely to find bugs. To alleviate such problems, a new regression suite practice, using random test generators to create regression suites on-the-fly, is becoming more common. In this practice, instead of maintaining tests, we generate test suites on-the-fly by choosing several specifications and generating a number of tests from each specification.     

Automatic boosting of cross-product coverage using Bayesian networks

Closing the feedback loop from coverage data to the stimuli generator is one of the main challenges in the verification process. Typically, verification engineers with deep domain knowledge manually prepare a set of stimuli generation directives for that purpose. Bayesian networks based CDG (coverage directed generation) systems have been successfully used to assist the process by automatically closing this feedback loop. However, constructing these CDG systems requires manual effort and a certain amount of domain knowledge from a machine learning specialist. We propose a new method that boosts coverage in the early stages of the verification process with minimal effort, namely a fully automatic construction of a CDG system that requires no domain knowledge. Experimental results on a real-life cross-product coverage model demonstrate the efficiency of the proposed method.     

On the Wyner-Ziv problem for individual sequences

We consider a variation of the Wyner-Ziv (W-Z) problem pertaining to lossy compression of individual sequences using finite-state encoders and decoders. There are two main results in this paper. The first characterizes the relationship between the performance of the best M-state encoder-decoder pair to that of the best block code of size /spl lscr/ for every input sequence, and shows that the loss of the latter relative to the former (in terms of both rate and distortion) never exceeds the order of (logM)//spl lscr/, independently of the input sequence. Thus, in the limit of large M, the best rate-distortion performance of every infinite source sequence can be approached universally by a sequence of block codes (which are also implementable by finite-state machines). While this result assumes an asymptotic regime where the number of states is fixed, and only the length n of the input sequence grows without bound, we then consider the case where the number of states M=M/sub n/ is allowed to grow concurrently with n. Our second result is then about the critical growth rate of M/sub n/ such that the rate-distortion performance of M/sub n/-state encoder-decoder pairs can still be matched by a universal code. We show that this critical growth rate of M/sub n/ is linear in n.     

Photoluminescence and electroluminescence imaging of perovskite solar cells

Fast camera‐based luminescence‐imaging measurements on perovskite solar cells are presented. The fundamental correlation between the luminescence intensity and the open circuit voltage predicted by the generalised Planck law is confirmed, enabling various quantitative methods for the detection of efficiency‐limiting defects to be applied to this new cell structure. Interstinegly, it is found that this fundamental correlation is valid only for light‐soaked devices. Copyright © 2015 John Wiley & Sons, Ltd.     

Photovoltaics literature survey (No. 115)

In order to help keep readers up‐to‐date in the field, each issue of Progress in Photovoltaics will contain a list of recently published journal articles that most relevant to its aims and scope. This list is drawn from an extremely wide range of journals, including IEEE Journal of Photovoltaics, Solar Energy Materials and Solar Cells, Renewable Energy, Renewable and Sustainable Energy Reviews, Journal of Applied Physics, and Applied Physics Letters. To assist the reader, the list is separated into broad categories, but please note that these classifications are by no means strict. Also note that inclusion in the list is not an endorsement of a paper's quality. If you have any suggestions please email Ziv Hameiri at ziv.hameiri@unsw.edu.au     

Synthesis and Characterization of Thrombin Conjugated γ‐Fe2O3 Magnetic Nanoparticles for Hemostasis

Thrombin is the final protease produced in the clotting pathways. Thrombin has been used in the clinic more than six decades for topical hemostasis and wound management. In human plasma the half‐life of thrombin is shorter than 15 seconds due to close control by inhibitors. In order to stabilize thrombin, this enzyme was conjugated covalently and physically to γ‐Fe₂O₃ magnetic nanoparticles. The physical conjugation was accomplished through adsorption of thrombin to BSA coating on the nanoparticles. The coagulant activity of the covalently bound thrombin was significantly lower than that of the physically adsorbed thrombin. Leakage of the physically bound thrombin into PBS containing 4% HSA was negligible. The physical conjugation of thrombin onto the nanoparticles stabilized the thrombin against its major inhibitor antithrombin III and improved its storage stability. At optimal CaCl₂ concentration, the clotting time by the bound thrombin is shorter than that of the free enzyme. This novel conjugated thrombin may be an efficient candidate for topical hemostasis and wound healing.     

Pulmonary thrombo-endarterectomy]

Chronic pulmonary thromboembolism is an underdiagnosed condition with major morbidity and mortality. Over the past year and a half, we diagnosed 6 new cases of which 3 underwent successful, pulmonary thrombo-endarterectomy (2 in San Diego, 1 in Jerusalem). All recovered fully and returned to normal, active life. We conclude that pulmonary thrombo-endarterectomy is a viable option for patients with chronic pulmonary thromboembolism.     

Constrained Information Combining: Theory and Applications for LDPC Coded Systems

This paper tightens previous information combining bounds on the performance of iterative decoding of binary low-density parity-check (LDPC) codes over binary-input symmetric-output channels by tracking the probability of erroneous bit in conjunction with mutual information. Evaluation of the new bounds as well as of other known bounds on different LDPC ensembles demonstrates sensitivity of the finite dimensional iterative bounds to lambda₂, the fraction of edges connected to degree 2 variable nodes