Probe for evaluating the absorbing and transport scattering properties of turbid fluids using low-cost time-of-flight technology

A probe is described that when immersed into a highly scattering fluid provides a measurement of its scattering and absorbing properties at a single optical wavelength. It uses recently available low-cost proximity sensor modules to estimate the mean flight times of photons diffusely transmitted between near-infrared sources and detectors at two different separations. The probe has been designed with a specific application for enabling the rapid and efficient production of fluids, which mimic the optical properties of biological tissues. The potential of the device is demonstrated using precalibrated solutions of intralipid, an intravenous nutrient, and absorbing dye. It is shown that a combination of time-of-flight measurements at two source–detector separations can uniquely specify the absorption coefficient and the transport scattering coefficient

Density Functional Study of Cubic to Rhombohedral Transition in α\alpha-AlF3_3

Under heating, $\alpha$-AlF$_3$ undergoes a structural phase transition from rhombohedral to cubic at temperature $T$ around 730 K. The density functional method is used to examine the $T$=0 energy surface in the structural parameter space, and finds the minimum in good agreement with the observed rhombohedral structure. The energy surface and electronic wave-functions at the minimum are then used to calculate properties including density of states, $\Gamma$-point phonon modes, and the dielectric function. The dipole formed at each fluorine ion in the low temperature phase is also calculated, and is used in a classical electrostatic picture to examine possible antiferroelectric aspects of this phase transition.Comment: A 6-page manuscript with 4 figures and 4 table

Trade Secret Law and Information Systems: Can Your Students Keep a Secret?

The impact of intellectual property (IP) law on information systems (IS) professionals in business cannot be overstated. The IS 2010 model curriculum guidelines for undergraduate IS programs stress the importance of information security and knowledge about IP. While copyright and patents are the most well-known types of IP, another, trade secrets, which involve confidential information generated by business to secure financial success, poses a unique challenge partly because IS professionals are often less familiar with trade secrets as a form of IP. Just as important is the crucial role IS plays in actually creating trade secrets. Information must not only be vital and proprietary but also its secrecy must be actively protected and maintained against data security challenges, including unethical behavior by disgruntled employees, corporate espionage, and inadvertent disclosure. Failure to do so results in a determination that information is not legally a protected trade secret. Unlike copyrights and patents, information cannot publically be designated as a trade secret prior to a challenge. Instead, organizations must prove the information is actually a trade secret. Critical to this proof are processes and internal systems businesses use to maintain information secrecy, which determine whether legal remedies exist if the trade secret is wrongfully divulged. This paper discusses trade secret law, methods used to secure trade secrets, and the role of IS in supporting and/or developing those methods. A class exercise provides IS students with insights into trade secret law and acceptable, ethical conduct of IS professionals who protect trade secrets

Virtual force field algorithm for a behaviour-based autonomous robot in unknown environments

The present paper describes a real-time motion-planning approach which lies in the integration of three techniques: fuzzy logic (FL), virtual force field (VFF), and boundary following (BF). The FL algorithm is used for velocity control based on sonar readings. The path-planning algorithm is based on the VFF and BF methods. The proposed navigation system differs from previous works in terms of using different algorithms for planning robot motion. Other improvements concern functional and computational aspects of the design and integration of the modules. The robot shows robust performance in complex situations and local minimum scenarios. Simulation results show the effectiveness of the developed system in various environments with long walls, U-shaped, maze-like, and other types of clutter

Inverse problem of photoelastic fringe mapping using neural networks

This paper presents an enhanced technique for inverse analysis of photoelastic fringes using neural networks to determine the applied load. The technique may be useful in whole-field analysis of photoelastic images obtained due to external loading, which may find application in a variety of specialized areas including robotics and biomedical engineering. The presented technique is easy to implement, does not require much computation and can cope well within slight experimental variations. The technique requires image acquisition, filtering and data extraction, which is then fed to the neural network to provide load as output. This technique can be efficiently implemented for determining the applied load in applications where repeated loading is one of the main considerations. The results presented in this paper demonstrate the novelty of this technique to solve the inverse problem from direct image data. It has been shown that the presented technique offers better result for the inverse photoelastic problems than previously published works

Identification and Implementation of Patterns Towards a Model of Environmental Sustainability

Much like the Quality Revolution did in the 1980\u27s, corporate sustainability has the potential to drive significant changes in the processes and structure of various organizations in the coming decade. With a rapidly growing global population and an ever increasing global demand for resources (Population-Resource-Center, 2012). Sustainability has emerged as one of the primary challenges that organizations will have to deal with in the 21st century. An increasing realization among business executives that profitability by itself is not enough as a measure of success is also driving the increased adoption of sustainable practices in the corporate world (Lowitt and Grimsley, 2009). Many of the non-financial concerns associated with sustainability are being rapidly recognized as ways to provide shareholder value in the long run. Although sustainability in the corporate world should emphasize economic, environmental and social sustainability, in this paper we will concentrate on the environmental issue and present a new model of best-of-breed practices for implementing environmental sustainability into an organization. To help develop this model we will examine the current literature, including a review of various case studies of corporations engaging in environmentally sustainable practices. We aim to identify practices that have been successful in various organizations and can be generalized and applied to other corporations. We believe that such a model can contribute to the understanding of, and the successful implementation of, environmentally sustainable practices throughout the corporate world

A comparison of APD and SPAD based receivers for visible light communications

Visible light communications (VLC) is an alternative method of indoor wireless communications that requires sensitive receivers. Ideally, single photon avalanche detectors (SPADs) could be used to create more sensitive receivers. However, the dead-time, finite output pulse width and photon detection efficiency of existing SPAD arrays limits their sensitivity and bandwidth. In this paper an accurate equation for the impact of dead-time on the sensitivity of a SPAD array is presented. In addition the impact of the width of the output pulses on the on-off keying (OOK) data rate is investigated. Finally, a comparison between receivers containing an APD and a large array of SPADs shows that although the receiver containing the SPAD is more sensitive in the dark the APD-based receiver is more sensitive in normal operating condition. However, the models that predict the performance of both receivers suggest that newer SPAD arrays will enable significant improvements in receiver sensitivity

Northern spotted owl nesting habitat under high potential wildfire threats along the California Coastal Redwood Forest

Large and severe wildfires, exacerbated by climate change and human behavior, are occurring more frequently in many forests across the western United States. While wildfire is a natural part of most terrestrial ecosystems, rapidly changing fire regimes have the potential to alter habitat beyond the adaptive capabilities of species. Spatial assessments of wildfire risks to species habitat may allow managers to pinpoint locations for management activities. To illustrate this, we spatially assessed wildfire risk within habitat that supports the nesting activity of the federally threatened northern spotted owl (Strix occidentalis caurina) in the California redwood coast ecoregion. To accomplish this, we built a scale-optimized ensemble nesting habitat suitability model and identified habitat with the highest wildfire hazard potential. Percent canopy cover at 100-m scale, slope at 400-m scale, and January precipitation at 800-m scale were the most influential environmental covariates for predicting northern spotted owl nesting habitat. Nearly 60% of nesting habitat was predicted to be at high or very high (>1986 index value) wildfire risks. We identified three areas in the Maple Creek Area of Humboldt County, Jackson State Demonstration Forest in Mendocino County, and Point Reyes National Seashore in Marin County, California with a high concentration of nesting habitat that are at a very high risk of experiencing high severity wildfires. We recommend these areas be targeted for future research to understand the impact of wildfire on northern spotted owl as well as management attention