Structural and electrical measurements of CdZnSe composite

TheI—Vcharacterization and the electrical resistivity of selenium rich Se₈₅Cd_15-xZn_x (x = 0, 3, 7, 11 and 15) system at room temperature have been studied. Samples were obtained using melt cooling technique. So prepared samples were then characterized in terms of their crystal structure and lattice parameter using X-ray diffraction method. The materials were found to be poly crystalline in nature, having zinc blend structure over the whole range of zinc concentration. The measurements ofI—V bdcharacteristics have been carried out at different temperatures from room to 140°C. The electrical resistivity of the samples with composition at room temperature has been found to vary between maximum 2.7 x 10⁸ Ωm and minimum 7.3 x 10⁵ Ωm and shows a maximum at 3 at. wt.% of Zn. The carrier activation energy of the samples with composition has also been determined and found to vary from 0.026 eV to 0.111 eV.     

Mapping the themes and intellectual structure of corporate university: co-citation and cluster analyses

Scientometrics - Corporate university is a unique form of educational arrangement to accomplish an organization’s goals by building the intellectual capital of its employees. In the academia,...     

Multi-objective optimization framework complying IEEE 802.15.6 communication standards for wireless body area networks

Wireless Networks - Wireless body area network (WBAN) routing protocols are primarily designed for improvement of network performance parameters such as network lifetime, throughput and latency....     

Filter-Based Mean-Field Inference for Random Fields with Higher-Order Terms and Product Label-Spaces

Recently, a number of cross bilateral filtering methods have been proposed for solving multi-label problems in computer vision, such as stereo, optical flow and object class segmentation that show an order of magnitude improvement in speed over previous methods. These methods have achieved good results despite using models with only unary and/or pairwise terms. However, previous work has shown the value of using models with higher-order terms e.g. to represent label consistency over large regions, or global co-occurrence relations. We show how these higher-order terms can be formulated such that filter-based inference remains possible. We demonstrate our techniques on joint stereo and object labelling problems, as well as object class segmentation, showing in addition for joint object-stereo labelling how our method provides an efficient approach to inference in product label-spaces. We show that we are able to speed up inference in these models around 10–30 times with respect to competing graph-cut/move-making methods, as well as maintaining or improving accuracy in all cases. We show results on PascalVOC-10 for object class segmentation, and Leuven for joint object-stereo labelling.     

Inter atomic force constants of binary and ternary tetrahedral semiconductors

In this paper, we present the expressions relating the inter atomic force constants like as bond-stretching force constant (α in N/m) and bond-bending force constant (β in N/m) for the binary (zinc blende structure) and ternary (chalcopyrite structure) semiconductors with the product of ionic charges (PIC) and crystal ionicity (f_i). Interatomic force constants of these compounds exhibit a linear relationship; when plot a graph between Interatomic force constants and the nearest neighbor distance d (Å) with crystal ionicity (f_i), but fall on different straight lines according to the product of ionic charges of these compounds. A fairly good agreement has been found between the observed and calculated values of the α and β for binary and ternary tetrahedral semiconductors.     

Do Crosscutting Concerns Cause Defects?

There is a growing consensus that crosscutting concerns harm code quality. An example of a crosscutting concern is a functional requirement whose implementation is distributed across multiple software modules. We asked the question, "How much does the amount that a concern is crosscutting affect the number of defects in a program?" We conducted three extensive case studies to help answer this question. All three studies revealed a moderate to strong statistically significant correlation between the degree of scattering and the number of defects. This paper describes the experimental framework we developed to conduct the studies, the metrics we adopted and developed to measure the degree of scattering, the studies we performed, the efforts we undertook to remove experimental and other biases, and the results we obtained. In the process, we have formulated a theory that explains why increased scattering might lead to increased defects.     

Distributed iterative quantization for interference characterization in wireless networks

We consider the problem of estimating the distance to a device transmitting in the 2.4 GHz ISM band that is interfering with users of an 802.11b wireless network. Accurate estimation of this quantity enables the wireless network to dynamically change its operating characteristics, such as its transmit power levels and channel assignments, to minimize this interference. The estimate is made by a cluster of wireless sensor motes deployed along the edge of an 802.11b network. The motes perform a 1-bit quantization of the Received Signal Strength (RSS) using a dithered quantization framework. The quantized bits are transmitted over a Binary Symmetric Channel (BSC) to the Cluster Head (CH), which then uses a Maximum-Likelihood Estimation (MLE) technique to estimate the unknown parameter. We propose a framework in which the CH uses an iterative parameter estimation scheme in which it provides low-overhead feedback to the motes to adjust their threshold values for the 1-bit dithered quantization process. Evaluation of the Root Mean Squared Error (RMSE) of this iterative scheme shows that it performs significantly better than iterative approaches in which all the motes use either identical thresholds or the non-identical thresholds proposed in Ribeiro and Giannakis (2006) [5] and [19]. Our iterative scheme also tracks sudden changes in the distance to the interferer and is robust to fluctuations in the crossover probability in the BSC.     

SampleSearch: Importance sampling in presence of determinism

The paper focuses on developing effective importance sampling algorithms for mixed probabilistic and deterministic graphical models. The use of importance sampling in such graphical models is problematic because it generates many useless zero weight samples which are rejected yielding an inefficient sampling process. To address this rejection problem, we propose the SampleSearch scheme that augments sampling with systematic constraint-based backtracking search. We characterize the bias introduced by the combination of search with sampling, and derive a weighting scheme which yields an unbiased estimate of the desired statistics (e.g., probability of evidence). When computing the weights exactly is too complex, we propose an approximation which has a weaker guarantee of asymptotic unbiasedness. We present results of an extensive empirical evaluation demonstrating that SampleSearch outperforms other schemes in presence of significant amount of determinism.     

Local transmitting boundaries for the generalized interpolation material point method

The boundary‐value problems of mechanics can be solved using the material point method with explicit solver formulations. In explicit formulations, even quasi‐static problems are solved as if dynamic, which means that waves are reflected at computational boundaries, generating spurious oscillations in the solution to the boundary‐value problem. Such oscillations can be reduced to a level such that they are barely noticeable with the use of transmitting boundaries. Current implementations of transmitting boundaries in the material point method are limited to the standard viscous boundary. The absence of any stiffness component in the standard viscous boundary may lead to an undesirable finite rigid‐body motion over time. This motion can be minimized through the adoption of the transmitting cone boundary that approximates the stiffness of the unbounded domain. This paper lays out the implementation of the transmitting cone boundary for the generalized interpolation material point method. The cone boundary reflection‐canceling tractions can be applied to either the edges or the centroids of material points; this paper discusses the implications of both approaches.     

Electrochemical hydrogen evolution and storage studies on bismuth nano hexagons

Bismuth nano hexagons were synthesized using potentiostatic electrodeposition and studied for their performance towards electrochemical hydrogen storage and evolution. Regular hexagons with edge length ≈ 500 nm and thickness ≈ 80 nm were observed in scanning electron microscopy (SEM). X-ray diffraction (XRD) pattern indicates the presence of poly-crystalline bismuth and bismuth oxide in rhombohedral and cubic phases respectively. X-ray photoelectron spectroscopy (XPS) studies further confirm the presence of two phases of bismuth i.e. elemental bismuth and bismuth (III) oxide. Results indicate that these nano hexagons show good hydrogen ion (H⁺) storage and successive hydrogen gas (H₂) evolution characteristics.