2,348 research outputs found
Evaluation and Design of Non-Lethal Laser Dazzlers Utilizing Microcontrollers
Current non-lethal weapons suffer from an inability to meet requirements for uses across many fields and purposes. The safety and effectiveness of these weapons are inadequate. New concepts have provided a weapon utilizing lasers to flashblind a target's visual system. Minimal research and testing have been conducted to investigate the efficiency and safety of these weapons called laser dazzlers. Essentially a laser dazzler is comprised of a laser beam that has been diverged with the use of a lens to expand the beam creating an intensely bright flashlight. All laser dazzlers to date are incapable of adjusting to external conditions automatically. This is important, because the power of these weapons need to change according to distance and light conditions. At long distances, the weapon is rendered useless because the laser beam has become diluted. At near distances, the weapon is too powerful causing permanent damage to the eye because the beam is condensed. Similarly, the eye adapts to brightness by adjusting the pupil size, which effectively limits the amount of light entering the eye. Laser eye damage is determined by the level of irradiance entering the eye. Therefore, a laser dazzler needs the ability to adjust output irradiance to compensate for the distance to the target and ambient light conditions. It was postulated if an innovative laser dazzler design could adjust the laser beam divergence then the irradiance at the eye could be optimized for maximum vision disruption with minimal risk of permanent damage. The young nature of these weapons has lead to the rushed assumptions of laser wavelengths (color) and pulsing frequencies to cause maximum disorientation. Research provided key values of irradiance, wavelength, pulsing frequency and functions for the optical lens system. In order for the laser dazzler to continuously evaluate the external conditions, luminosity and distance sensors were incorporated into the design. A control system was devised to operate the mechanical components meeting calculated values. Testing the conceptual laser dazzlers illustrated the complexities of the system. A set irradiance value could be met at any distance and light condition, although this was accomplished by less than ideal methods. The final design included two lasers and only one optical system. The optical system was only capable of providing constant irradiance of one laser or the other allowing only single laser operation. For dual laser operation, the optical system was calibrated to offset the losses of each laser as distance was changed. Ultimately, this provided a constant combined irradiance with a decreasing green irradiance and increasing red irradiance as distance was increasing. Future work should include enhancements to the mechanical components of the laser dazzler to further refine accuracy. This research was intended to provide a proof of concept and did so successfully
An investigation into internet use by 45-54 year olds
This research set out to determine how frequently, and for what purpose, members of the 45-54 year old generation used the internet, specifically whether they used it to socialise and for domestic purposes more frequently than they did for educational and work related purposes. This area of research is particularly fascinating because members of that generation grew up in a world with no internet, to one in 2009 where there were an estimated 1.56 billion world-wide internet users. A non-experimental research design was chosen using a questionnaire issued by email. Participants had a choice of completing the questionnaire and posting it back or completing it online. To minimise the risk of unsuitable recruits, and given the specific age related nature of the pre-defined research sample, non-probability purposive sampling techniques were used to arrive at the sampling frame of convenience. The main findings were that respondents stated that they used the internet for socialising and domestic purposes more frequently than they did for work and educational purposes. Therefore the null hypothesis was rejected ( that: "45-54 year olds do not use the internet to socialise and for domestic purposes more frequently than they do for educational and work related activities"). A weak relationship was found between gender and internet usage. Males, on average, used the internet more frequently than females for both social & domestic and work & educational purposes. This finding was similar to that of other recent UK based research. No statistically significant differences in internet use were found between the main roles or professions of respondents. However internet use was found to increase as the level of educational qualification increased broadly in line with the findings of other research. Those with higher educational qualifications in this study used the internet significantly more for work and educational purposes. In addition those who lived in rural areas used the internet significantly more for work & educational purposes, but no statistically significant difference in frequency of internet uses was found for domestic & social purposes. Those from Greater Manchester were the most frequent users of the internet for domestic & social purposes and N. Wales were the lowest. Finally, respondents from married households with children were the most active internet users, but no significant differences were detected when exploring that and other household types. Other studies had found significant differences between household types with internet use increasing as the number of household members increased because their internet use was driven by their need to maintain and coordinate multiple relationships
A renormalisation-group treatment of two-body scattering
Nonrelativistic two-body scattering by a short-ranged potential is studied
using the renormalisation group. Two fixed points are identified: a trivial one
and one describing systems with a bound state at zero energy. The eigenvalues
of the linearised renormalisation group are used to assign a systematic
power-counting to terms in the potential near each of these fixed points. The
expansion around the nontrivial fixed point is shown to be equivalent to the
effective-range expansion.Comment: 6 pages (RevTeX), 1 figure (epsf); picture of RG flow and more
discussion of momentum dependence adde
DISTRIBUTION CHOICE UNDER NULL PRIORS AND SMALL SAMPLE SIZE
Defining appropriate probability distributions for the variables in an economic model is an important and often arduous task. This paper evaluates the performance of several common probability distributions under different distributional assumptions when sample sizes are small and there is limited information about the data.Research Methods/ Statistical Methods,
Progress Report to the TNRC for Analysis of the Economics of Atrazine Remediation for Representative Grain Farms in the Aquilla Watershed, Hill County, Texas: Subtasks 4.0-4.4
Four alternative BMPs for atrazine remediation were reported by Harmon and Wang for the study area. The BMPs involved alternative incorporation practices, tillage operations, and sediment ponds. Harmon and Wang reported no statistical difference in corn yields under the alternative BMPs. An economic analysis of four alternative best management practices (BMPs) for atrazine remediation in Hill County, Texas, was performed by the Agricultural and Food Policy Center (AFPC) at Texas A&M University. Using the farm-level economic simulation model FLIPSIM, AFPC scientists analyzed the financial effects of the alternative BMPs on the Texas Blackland Prairie representative farm. This farm consists of 2,000 dryland acres, divided among corn (600 acres), sorghum (750 acres), wheat (250 acres), and native pasture (150 acres). This farm also maintains a small beef cowherd. Regularly updated, the AFPC maintains more than 80 farms across the nation that form the basis for probabilistic-based agricultural policy evaluation.Agricultural and Food Policy, Resource /Energy Economics and Policy,
The Impact of Gender on Productive and Social Activities
Increasing numbers of women are becoming members of the labor force. Yet it is not clear to what extent working for wages relieves women of their responsibility for traditional and non-paid activities, such as household work and child care. This study examines the impact of gender on the division of domestic labor among working women and men. This research focuses on three kinds of productive activities (paid work, household work, and child care). In addition to productive activities, two kinds of social activities (time spent with relatives and friends, and time spent in entertainment activities) are included. This research also focuses on a select category of workers--namely, professionals (including lawyers, social workers, high school teachers, and college teachers). These types of careers may place special burdens on women. Finally, several control variables are included in the analysis, such as social status and life style factors, work factors, and several potentially relevent interaction terms. The findings indicate that gender is a major influence on all three types of productive activities. The strongest impact is on domestic work, including associations for gender by itself as well as in interaction with age, having a dependent child, and marital status. On child care, gender interacts with having a dependent child. Gender has almost no effect on social activities, with the only significant association a weak interaction between gender and marital status. These findings raise questions about the pervasiveness of sex role changes in this society. Not only does entering the labor force fail to relieve women of their traditional role responsibilities, it may in fact lead to an increase in what is expected of them
STOCHASTIC EFFICIENCY ANALYSIS USING MULTIPLE UTILITY FUNCTIONS
Evaluating the risk of a particular decision depends on the risk aversion of the decision maker related to the underlying utility function. The objective of this paper is to use stochastic efficiency with respect to a function (SERF) to compare the ranking of risky alternatives using alternative utility functional forms.Research Methods/ Statistical Methods,
Stochastic efficiency analysis with risk aversion bounds: a simplified approach
A method of stochastic dominance analysis with respect to a function (SDRF) is described and illustrated. The method, called stochastic efficiency with respect to a function (SERF), orders a set of risky alternatives in terms of certainty equivalents for a specified range of attitudes to risk. It can be applied for conforming utility functions with risk attitudes defined by corresponding ranges of absolute, relative or partial risk aversion coefficients. Unlike conventional SDRF, SERF involves comparing each alternative with all the other alternatives simultaneously, not pairwise, and hence can produce a smaller efficient set than that found by simple pairwise SDRF over the same range of risk attitudes. Moreover, the method can be implemented in a simple spreadsheet with no special software needed.Risk and Uncertainty,
Stochastic Optimization: An Application to Sub-Arctic Dairy Farming
The paper demonstrates how a deterministic farm linear programming (LP) model can be made stochastic and simulated using Solver and Simetar© in Excel©. The demonstration is conducted with an LP-model for a dairy farm for a sub arctic region of Norway. The income risks arising from variation in milk and crop yields due to winter damage in leys and pastures have been quantified for farms demonstrating low, medium and high forage yield risk. The estimated distribution of farm profit will be skewed to the left, indicating a downside risk. In the presence of risks, farmers maximize income by producing the milk quota with using surplus forage for meat production. The analysis demonstrated here may assist farmers and farm managers in improving sensitivity analysis for risky variables in farm LP models.dairy production, Northern Norway, stochastic optimization, stochastic simulation, yield risks, Livestock Production/Industries,
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