Variation aware analysis of bridging fault testing

This paper investigates the impact of process variation on test quality with regard to resistive bridging faults. The input logic threshold voltage and gate drive strength parameters are analyzed regarding their process variation induced influence on test quality. The impact of process variation on test quality is studied in terms of test escapes and measured by a robustness metric. It is shown that some bridges are sensitive to process variation in terms of logic behavior, but such variation does not necessarily compromise test quality if the test has high robustness. Experimental results of Monte-Carlo simulation based on recent process variation statistics are presented for ISCAS85 and -89 benchmark circuits, using a 45nm gate library and realistic bridges. The results show that tests generated without consideration of process variation are inadequate in terms of test quality, particularly for small test sets. On the other hand, larger test sets detect more of the logic faults introduced by process variation and have higher test quality

Blade Sharpness and its Effect on the Testing of Body Armours

Factors such as edge sharpness and tip sharpness have been identified by Horsfall,1 as keyvariables in the testing of stab and slash resistant armours. This paper evaluates the influenceof blade sharpness on the mechanics of penetration and its relationship with a variety ofmaterials used for body armour systems. The differences in performance between blunt andsharp blades are compared by dynamic tests using an instrumented drop tower, measuringpeak loads and energy to penetration. Variance in the initial impact forces required topenetrate body armour between blunt and sharp blades is shown. However, the total energyto penetration for both sharp and blunt knives was found to be similar for a specific bodyarmour system. Dynamic tests were also used to evaluate the effect of wear on bladeperformance by the comparison of the initial loads for puncture and depth of penetration onaramid and metallic armour systems. The effect of sharpness on the reproducibility of testresults is also investigated and discussed. Various test methods are described for themeasurement of sharpness for both stab and slash and compared. The recent development ofa new non-destructive proof test method to measure tip and edge sharpness is also described

Dynamic Voltage Scaling Aware Delay Fault Testing

The application of Dynamic Voltage Scaling (DVS) to reduce energy consumption may have a detrimental impact on the quality of manufacturing tests employed to detect permanent faults. This paper analyses the influence of different voltage/frequency settings on fault detection within a DVS application. In particular, the effect of supply voltage on different types of delay faults is considered. This paper presents a study of these problems with simulation results. We have demonstrated that the test application time increases as we reduce the test voltage. We have also shown that for newer technologies we do not have to go to very low voltage levels for delay fault testing. We conclude that it is necessary to test at more than one operating voltage and that the lowest operating voltage does not necessarily give the best fault cover

Optimum Saving and Growth: Harrod on Dynamic Welfare Economics

In the 1960s and 1970s Harrod shifted the emphasis of his research in economic dynamics from the study of business cycles (instability principle) to the investigation of the growth process. As part of that, he restated his concept of the natural growth rate as an optimum welfare rate. The present paper examines Harrod's dynamic welfare economics, built around his concept of optimum saving developed as a reaction to Ramsey's approach to capital accumulation. It is shown that, according to Harrod, the saving rate does not affect the long-run growth rate of per capita income, which is determined by technical progress. Moreover, the economy will grow at the natural (full employment) rate only if economic policy is able to bring saving to its "optimum" level in macroeconomic equilibrium. Harrod's interest in optimal growth was motivated by his double concern with growth policy in mature economies and economic development in poor countries

Bacterial Active Community Cycling in Response to Solar Radiation and Their Influence on Nutrient Changes in a High-Altitude Wetland

Indexación: Web of Science; Scopus.Microbial communities inhabiting high-altitude spring ecosystems are subjected to extreme changes in solar irradiance and temperature throughout the diel cycle. Here, using 16S rRNA gene tag pyrosequencing (cDNA) we determined the composition of actively transcribing bacteria from spring waters experimentally exposed through the day (morning, noon, and afternoon) to variable levels of solar radiation and light quality, and evaluated their influence on nutrient recycling. Solar irradiance, temperature, and changes in nutrient dynamics were associated with changes in the active bacterial community structure, predominantly by Cyanobacteria, Verrucomicrobia, Proteobacteria, and 35 other Phyla, including the recently described Candidate Phyla Radiation (e.g., Parcubacteria, Gracilibacteria, OP3, TM6, SR1). Diversity increased at noon, when the highest irradiances were measured (3.3-3.9 H', 1125 W m(-2)) compared to morning and afternoon (0.6-2.8 H'). This shift was associated with a decrease in the contribution to pyrolibraries by Cyanobacteria and an increase of Proteobacteria and other initially low frequently and rare bacteria phyla (< 0.5%) in the pyrolibraries. A potential increase in the activity of Cyanobacteria and other phototrophic groups, e.g., Rhodobacterales, was observed and associated with UVR, suggesting the presence of photo activated repair mechanisms to resist high levels of solar radiation. In addition, the percentage contribution of cyanobacterial sequences in the afternoon was similar to those recorded in the morning. The shifts in the contribution by Cyanobacteria also influenced the rate of change in nitrate, nitrite, and phosphate, highlighted by a high level of nitrate accumulation during hours of high radiation and temperature associated with nitrifying bacteria activity. We did not detect ammonia or nitrite oxidizing bacteria in situ, but both functional groups (Nitrosomona and Nitrospira) appeared mainly in pyrolibraries generated from dark incubations. In total, our results reveal that both the structure and the diversity of the active bacteria community was extremely dynamic through the day, and showed marked shifts in composition that influenced nutrient recycling, highlighting how abiotic variation affects potential ecosystem functioning.http://journal.frontiersin.org/article/10.3389/fmicb.2016.01823/ful

Use and perception of collars for companion cats in New Zealand

Aims: To investigate public perceptions of the use of collars for companion cats in New Zealand. To understand perceptions around safety and efficacy of collar use. Methods: An online questionnaire was distributed to members of the public via social media. The questionnaire collected details of respondents, cat ownership status, and responses to a number of questions regarding collar use in cats. Data were analysed using SPSS analytical software v21.0 for Windows (IBM Inc., Chicago IL, USA). Results were considered significant if p≤0.05. Results: A total of 512 responses were collected, 393 (76.9%) respondents reported owning at least one cat at the time of survey, of which 141 (36.4%) stated that at least some of their cats wore collars and 211 (54%) had at least one of their cats micro-chipped. Of the respondents with a pet cat, 351 (90%) allowed their cats outdoor access at least some of the time. Respondents 20 used collars for identification, and to reduce predation of birds and other animals. Reasons for not using collars included cat intolerance of collars, repeated collar loss and concern over collar safety. Respondents felt collars could cause injury if caught on objects, or if too tight, and many believed ‘not all cats will tolerate a collar’. Significant differences were found between cat owners and non-owners regarding whether cats were important for pest control; whether cats will tolerate collars; whether being well fed influences cat hunting behaviour; whether cats should be kept indoors at night; and whether a cat without a collar was likely to be a stray. Respondents trusted veterinarians and the SPCA most as sources of pet care information. Conclusion: Collar use for companion cats in New Zealand appeared to be low. Cat owners perceived a number of barriers to the use of collars which may be imagined, or result from incorrect use. Collars may be useful for improving animal welfare allowing rapid identification , improved rates of returns to owners and prompt medical interventions in the case of injury. Collars with attached devices such as bells are also useful to reduce the impact of domestic cats on both native and introduced wildlife, and may improve public perceptions of stray/wandering cats. Relevance: A number of concerns have been raised in recent years about the negative impacts of cats on New Zealand’s natural environment, and the possibility of poor welfare among unowned cats. Understanding the perceived importance of cat collars and exploration of the perceived barriers to their use are vital to enhance our understanding of cat ownership, cat identification and impact of cat predation. This understanding can help to guide development of policies and practices to improve animal welfare, reduce the negative impact of pet predation, and promote responsible pet ownership

Ecological speciation in a generalist consumer expands the trophic niche of a dominant predator

Ecological speciation - whereby an ancestral founder species diversifies to fill vacant niches - is a phenomenon characteristic of newly formed ecosystems. Despite such ubiquity, ecosystem-level effects of such divergence remain poorly understood. Here, we compared the trophic niche of European whitefish (Coregonus lavaretus) and their predators in a series of contrasting subarctic lakes where this species had either diversified into four ecomorphologically distinct morphs or instead formed monomorphic populations. We found that the trophic niche of whitefish was almost three times larger in the polymorphic than in the monomorphic lakes, due to an increase in intraspecific specialisation. This trophic niche expansion was mirrored in brown trout (Salmo trutta), a major predator of whitefish. This represents amongst the first evidence for ecological speciation directly altering the trophic niche of a predator. We suggest such mechanisms may be a common and important - though presently overlooked - factor regulating trophic interactions in diverse ecosystems globally.Peer reviewe