Microscopy refocusing and dark-field imaging by using a simple LED array

The condenser is one of the main components in most transmitted light compound microscopes. In this Letter, we show that such a condenser can be replaced by a programmable LED array to achieve greater imaging flexibility and functionality. Without mechanically scanning the sample or changing the microscope setup, the proposed approach can be used for dark-field imaging, bright-field imaging, microscopy sectioning, and digital refocusing. Images of a starfish embryo were acquired by using such an approach for demonstration

Best and worst case permutations for random online domination of the path

We study a randomized algorithm for graph domination, by which, according to a uniformly chosen permutation, vertices are revealed and added to the dominating set if not already dominated. We determine the expected size of the dominating set produced by the algorithm for the path graph $P_n$ and use this to derive the expected size for some related families of graphs. We then provide a much-refined analysis of the worst and best cases of this algorithm on $P_n$ and enumerate the permutations for which the algorithm has the worst-possible performance and best-possible performance. The case of dominating the path graph has connections to previous work of Bouwer and Star, and of Gessel on greedily coloring the path.Comment: 13 pages, 1 figur

Analysis of the Australian web threat landscape

One in approximately eight Australian IPs are exposed to one or more web threats on any typical day, finds this report released by an Australian Research Council (ARC) Linkage Project involving Trend Micro and Deakin University. The researchers’ analysed malicious activity from over 200,000,000 web requests per day from Australia, with around 400,000 of these issued to malicious web pages.Abstract This report discusses threats on the Australian web landscape. We analyse web logs and provide statistics on what is happening to the average Australian user of the world-wide web. The analysis covers aspects such as the volume and timing of web threats attacking Australians and the source geography of the malicious activity. We look at a case study of a web attack that had global reach and describe the impact of this attack on Australian web users

RATIONAL INCOMPATIBILITY WITH INTERNATIONAL PRODUCT STANDARDS

This paper considers the incentives of firms to conform to an exogenous international product standard. Product standardization enables traditional, price-based international competition. But the existence of redesign costs or network effects creates market frictions that diminish the incentive to standardize if there already exists a different technology in an established market. This leads to multi-attribute competition between products and will generally reduce trade flows. Not only do incumbent firms using a different technology have an incentive to deviate from the international standard, but a host country government that is also concerned for the welfare of consumers who own the old technology has no incentive to enforce the international standard. Indeed, the government may value deviation from the international standard more than the firm does, thereby creating incentives to adopt and enforce technical barriers to trade. The results highlight the challenge lock-in effects pose to the international standard-setting process.compatibility, international standardization, network effects, redesign costs, technical barriers to trade, International Relations/Trade, F02, F13, F15, L11, L13, L51,