Worst case Cramer-Rao bounds for parametric estimation ofsuperimposed signals with applications

The problem of parameter estimation of superimposed signals in white Gaussian noise is considered. The effect of the correlation structure of the signals on the Cramer-Rao bounds is studied for both the single and multiple experiment cases. The best and worst conditions are found using various criteria. The results are applied to the example of parameter estimation of superimposed sinusoids, or plane-wave direction finding in white Gaussian noise, and best and worst conditions on the correlation structure and relative phase of the sinusoids are found. This provides useful information on the limits of the resolvability of sinusoid signals in time series analysis or of plane waves in array processing. The conditions are also useful for designing worst-case simulation studies of estimation algorithms, and for the design of minimax signal acquisition and estimation procedures, as demonstrated by an example     

Short-term group treatment for adult children of alcoholics.

Highly significant test score changes of adult children of alcoholics supported the effectiveness of individual therapy in short-term groups. 24 Ss were tested on measures of loneliness (UCLA Loneliness Scale); anxiety, hostility, and depression (Multiple Affect Adjective Check List—Revised [MAACL—R]); and interpersonal dependency (Interpersonal Dependency Inventory [IDI]). MAACL—R Anxiety and Depression scores declined. MAACL—R Hostility scores rose at the end of the treatment and then declined sharply 8 wks later. Increases toward test norms occurred on the IDI Lack of Social Confidence scale. Scores on the IDI Emotional Reliance on Another Person scale, the IDI Assertion of Autonomy scale, and the UCLA Loneliness Scale fell within scale norms and showed little change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On Radiant Network Models of Thermocouple Error in Pre and Post Flashover Compartment Fires

Thermocouples are often used to obtain gas temperature measurements in compartment fires. Such measurements are subject to a thermal lag during fire growth, but the main problem is a steady-state error induced by radiant heat transfer at the thermocouple surface. This error is sensitive to thermal parameters of the flame, compartment structure, thermocouple surface and combustion products; and is also influenced by the size and position of both the flame and thermocouple. The literature contains models of varying sophistication to enable an assessment of steady-state error. A model is now proposed that makes use of the concept of radiosity. Developed from radiant network theory, the model can be applied to both pre-flashover and post-flashover conditions. Experiments have been performed using different sizes of thermocouple and the models compared. The simpler models pre-date the more sophisticated and predict much larger errors than the latest published and current versions.     

Convective diffusion of particles deposition under electrostatics from turbulently-mixed conditions

A theoretical model is presented to describe inertialess particle deposition onto smooth surfaces under the influence of electrostatic force. Both Boltzmann and combined diffusion and field charging mechanisms are investigated. A modified Fick's law equation accounting for Brownian and turbulent diffusion, spatially-independent external force, i.e. gravitational and Coulombic force, is presented based on the simplified three-layer model. The results show that the concentration boundary layer thickness is very thin and the previous three-layer model can be further simplified. The Coulombic force influences the particle deposition significantly and for considerably high charge and electric field, deposition is independent on turbulent intensity. The model predictions agree very well with the literature DNS results.     

A systematic methodology for determining/optimizing a machine vision system's capability

This paper presents a systematic methodology based on Taguchi methods to determine and optimize a machine vision system's capability. Seven factors were studied in anL ₂₇(3¹³) orthogonal array: lens type, color of the background, distance between two objects on the target, distance between the camera and the target, filter, lighting source, and angle between the optic axis of the camera and the surface of the target. The optimal factor-level combination was determined from the experiment results, and the response surface plots were provided for a user to choose an alternative. Because this Taguchi methods-based methodology is simple and effective, it is recommended for determining and optimizing a machine vision system's capability.     

Analyzing fault and severity in pedestrian–motor vehicle accidents in China

The number of pedestrian–motor vehicle accidents and pedestrian deaths in China surged in recent years. However, a large scale empirical research on pedestrian traffic crashes in China is lacking. In this study, we identify significant risk factors associated with fault and severity in pedestrian–motor vehicle accidents. Risk factors in several different dimensions, including pedestrian, driver, vehicle, road and environmental factors, are considered. We analyze 6967 pedestrian traffic accident reports for the period 2006–2010 in Guangdong Province, China. These data, obtained from the Guangdong Provincial Security Department, are extracted from the Traffic Management Sector-Specific Incident Case Data Report. Pedestrian traffic crashes have a unique inevitability and particular high risk, due to pedestrians’ fragility, slow movement and lack of lighting equipment. The empirical analysis of the present study has the following policy implications. First, traffic crashes in which pedestrians are at fault are more likely to cause serious injuries or death, suggesting that relevant agencies should pay attention to measures that prevent pedestrians from violating traffic rules. Second, both the attention to elderly pedestrians, male and experienced drivers, the penalty to drunk driving, speeding, driving without a driver's license and other violation behaviors should be strengthened. Third, vehicle safety inspections and safety training sessions for truck drivers should be reinforced. Fourth, improving the road conditions and road lighting at night are important measures in reducing the probability of accident casualties. Fifth, specific road safety campaigns in rural areas, and education programs especially for young children and teens should be developed and promoted. Moreover, we reveal a country-specific factor, hukou, which has significant effect on the severity in pedestrian accidents due to the discrepancy in the level of social insurance/security, suggesting that equal social security level among urban and rural people should be set up. In addition, establishing a comprehensive liability distribution system for non-urban areas and roadways will be conducive to both pedestrians’ and drivers’ voluntary compliance with traffic rules.     

Observations on Federal energy research and development—December 1974

Much of our country's present stance in energy R&D is an embodiment of the recommendations presented in the Dixy Lee Ray report, “The Nation's Energy Future” (NEF).^Pa Since that report appeared just one year ago, the Energy Research and Development Administration (ERDA)^∥ has been established, and the Project Independence Blueprint (PIB)¹¹     

Sputtered Cd1−xZnxTe films for top junctions in tandem solar cells

Cd_1−xZn_xTe alloy films with 1.6 and 1.7 eV band gaps were deposited by RF magnetron sputtering from targets made either of mixed powders or alloys of CdTe and ZnTe (25% and 40%). High-quality polycrystalline films with the (1 1 1) preferred orientation were obtained. The films were characterized using X-ray diffraction (XRD), scanning electron microscopy, resistivity, optical absorption, Raman, and photoluminescence. The EDS, XRD, and optical absorption analysis indicated that the x-value of the as-grown films were typically 0.20 and 0.30 for films sputtered from 25% and 40% ZnTe containing targets, respectively. The as-deposited alloy films exhibit quite low photovoltaic performance when used to make cells with CdS as the hetero-junction partner. Therefore, we have studied various post-deposition treatments with vapors of chlorine-containing materials, CdCl₂ and ZnCl₂, in dry air or H₂/Ar ambient at 390 °C. The best performance of a Cd_1−xZn_xTe cell (, ) was found for treatment with vapors of the mixed CdCl₂+0.5%ZnCl₂ in an H₂/Ar ambient after pre-annealing at 520 °C in pure H₂/Ar.     

H2AX phosphorylation in response to DNA double-strand break formation during bystander signalling: effect of microRNA knockdown

Upon DNA double-strand break (DSB) formation, hundreds of H2AX molecules in the chromatin flanking the break site are phosphorylated on serine residue 139, termed gamma-H2AX, so that virtually every DSB site in a nucleus can be visualised within 10 min of its formation using an antibody to gamma-H2AX. One application of this sensitive assay is to examine the induction of DNA double-strand damage in subtle non-targeted cellular effects such as the bystander effect. Here whether microRNA (miRNA) serve as a primary signalling mechanism for bystander effect propagation by comparing matched human colon carcinoma cell lines with wild-type or depleted levels of mature miRNAs was investigated. No major differences were found in the levels of induced gamma-H2AX foci in the tested cell lines, indicating that though miRNAs play a role in bystander effect manifestation, they appear not to be the primary bystander signalling molecules in the formation of bystander effect-induced DSBs.     

Facile synthesis and growth mechanism of Ni-catalyzed GaAs nanowires on non-crystalline substrates

GaAs nanowires (NWs) have been extensively explored for next generation electronics, photonics and photovoltaics due to their direct bandgap and excellent carrier mobility. Typically, these NWs are grown epitaxially on crystalline substrates, which could limit potential applications requiring high growth yield to be printable or transferable on amorphous and flexible substrates. Here, utilizing Ni as a catalytic seed, we successfully demonstrate the synthesis of highly crystalline, stoichiometric and dense GaAs NWs on amorphous SiO(2) substrates. Notably, the NWs are found to grow via the vapor-solid-solid (VSS) mechanism with non-spherical NiGa catalytic tips and low defect densities while exhibiting a narrow distribution of diameter (21.0 ± 3.9 nm) uniformly along the entire length of the NW (>10 μm). The NWs are then configured into field-effect transistors showing impressive electrical characteristics with I(ON)/I(OFF) > 10(3), which further demonstrates the purity and crystal quality of NWs obtained with this simple synthesis technique, compared to the conventional MBE or MOCVD grown GaAs NWs.