Ionic liquid mediated surface micropatterning of polymer blends

A polymer of intrinsic porosity (i.e., PIM‐1) has been blended with different ionic liquids (ILs) in order to evaluate the effect of the ILs on the microstructure of the polymer blend. [C₈MIM][Cl], [BMIM][DCa], [BMPyr][DCa], and [BMIM][Tf₂N] have been selected and were mixed with PIM‐1. Polymer blends containing up to 80 wt % of ILs were prepared by a casting method with chloroform as solvent. SEM images show that during the film formation a structuring of the surface appears depending on the nature and the concentration of ILs, with appearance of well‐defined microstructure in the case of [BMIM][Tf₂N] and [BMIM][DCa]. In the case of [BMIM][Tf₂N]/PIM‐1 film, the lower IL concentration induces the denser film with small micropatterns onto the surface. AFM analysis indicates that the ILs are well dispersed on the surface. X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and water contact angle measurements show that a gradient of IL concentration is observed across the film thickness. It is demonstrated that ILs are versatile co‐solvents for inducing controlled micropatterns in polymer membrane surfaces. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46109.     

Susceptible Workload Evaluation and Protection using Selective Fault Tolerance

Low power fault tolerance design techniques trade reliability to reduce the area cost and the power overhead of integrated circuits by protecting only a subset of their workload or their most vulnerable parts. However, in the presence of faults not all workloads are equally susceptible to errors. In this paper, we present a low power fault tolerance design technique that selects and protects the most susceptible workload. We propose to rank the workload susceptibility as the likelihood of any error to bypass the logic masking of the circuit and propagate to its outputs. The susceptible workload is protected by a partial Triple Modular Redundancy (TMR) scheme. We evaluate the proposed technique on timing-independent and timing-dependent errors induced by permanent and transient faults. In comparison with unranked selective fault tolerance approach, we demonstrate a) a similar error coverage with a 39.7% average reduction of the area overhead or b) a 86.9% average error coverage improvement for a similar area overhead. For the same area overhead case, we observe an error coverage improvement of 53.1% and 53.5% against permanent stuck-at and transition faults, respectively, and an average error coverage improvement of 151.8% and 89.0% against timing-dependent and timing-independent transient faults, respectively. Compared to TMR, the proposed technique achieves an area and power overhead reduction of 145.8% to 182.0%.     

Road to Next Generation Mobile Networks: An Evolutionary Dynamics Approach

One of the major challenges that mobile operators (MOs) are faced with nowadays is the transition to 4th Generation (4G) mobile communication technologies. The main reason for this lies on the reluctance of MOs to invest in a new technology without being sure about its success. The current paper investigates the decision-making procedures of a MO that wishes to migrate from its current technology type to 4G. Traditionally, the decision of deploying a new technology has been based on the analysis of similar implementations in other countries. However, such approaches can be inefficient and time consuming, as there are discrepancies concerning the technological progress among different countries. To this end, the authors employ evolutionary game theory to model the interactions of the MO’s decisions and the subscribers’ needs, and propose a practical and efficient qualitative model that identifies the circumstances under which the transition towards 4G networking can be facilitated. Specifically, the mathematical foundation of the decision making process is provided and the key role of the charging price and the quality of experience by the subscribers for using 4G connectivity is proven. With the process of 4G deployment still ongoing, this paper aims to present an analysis that can be used supplementary to the decision process of a MO that aims to evolve his network.     

End-to-End Performance Analysis of Millimeter Wave Triple-Hop Backhaul Transmission Systems

Frequencies above 10 GHz nowadays may be employed either for backhaul networks of mobile communication access networks or for broadband fixed wireless access networks. Millimeter wave networks can afford large bandwidth by carrying the aggregate traffic through different network nodes. Consequently, many line-of-sight multi-hop transmissions may occur. At these frequency bands, rain attenuation is the dominant fading mechanism that aggravates the outage performance of these networks. The objective of this paper is the presentation of analytical models for the calculation of the end-to-end performance analysis of a triple-hop system with non-regenerative and regenerative relays using the trivariate lognormal distribution along with a physical model for the calculation of the correlation coefficients among the rain fading channels. Moreover, an accurate rain attenuation time series synthesizer based on multi-dimensional first order Stochastic Differential eqnarrays is employed in order to validate the analytical results. Finally, extended numerical results investigate the impact of various operational and geographical parameters, as well as the influence of the arbitrary position of the relays on the outage system performance.     

Visual tracking using the Earth Mover's Distance between Gaussian mixtures and Kalman filtering

In this paper, we demonstrate how the differential Earth Mover's Distance (EMD) may be used for visual tracking in synergy with Gaussian mixtures models (GMM). According to our model, motion between adjacent frames results in variations of the mixing proportions of the Gaussian components representing the object to be tracked. These variations are computed in closed form by minimizing the differential EMD between Gaussian mixtures, yielding a very fast algorithm with high accuracy, without recurring to the EM algorithm in each frame. Moreover, we also propose a framework to handle occlusions, where the prediction for the object's location is forwarded to an adaptive Kalman filter whose parameters are estimated on line by the motion model already observed. Experimental results show significant improvement in tracking performance in the presence of occlusion.     

How student’s personality traits affect Computer Based Assessment Acceptance: Integrating BFI with CBAAM

Researchers in the Information Systems (IS) field have put considerable effort on identifying how personality affects technology acceptance. This study is a further step towards this direction within the context of Computer Based Assessment (CBA). Particularly, it investigates how the five personality factors affect the most important variables regarding CBA’s acceptance. For this purpose, 117 participants were required to complete a survey questionnaire. The questionnaire included the Big Five Inventory (BFI) questions in order to measure the five personality traits, and 23 items regarding student’s perceptions. Partial Least Squares (PLS) was used to test the measurement and the structural model. Results underline that Neuroticism has significant negative effect on Perceived Usefulness and on Goal Expectancy, Agreeableness determines Social Influence and Perceived Ease of Use, Conscientiousness defines Perceived Ease of Use, while Extroversion and Openness explain Perceived Importance. Important implications of these results are discussed.