Search results for " ra"
showing 10 items of 21965 documents
Linear fusion of interrupted reports in cooperative spectrum sensing for cognitive radio networks
2015
Interrupted reporting has recently been introduced as an effective method to increase the energy efficiency of cooperative spectrum sensing schemes in cognitive radio networks. In this paper, joint optimization of the reporting and fusion phases in a cooperative sensing with interrupted reporting is considered. This optimization aims at finding the best weights used at the fusion center to construct a linear fusion of the received interrupted reports, jointly with Bernoulli distributions governing the statistical behavior of the interruptions. The problem is formulated by using the deflection criterion and as a nonconvex quadratic program which is then solved for a suboptimal solution, in a…
Issues with a course that emphasizes self-direction
2013
In this paper, we examine a master's level course that emphasizes self-direction on the part of students. The course is run by weekly group assignments and requires independent work such that only one mandatory classroom session is arranged each week. Our specific research interests are how students responded to the setting of this kind and whether they demonstrated self-direction during the course. We surveyed the students' view of the course, their group work experience, and their study habits, and analyzed the resultant survey data for themes. The results suggest that while the pass rate was considerably high and the course was regarded as well-organized by the students, there were sever…
Assessing game experience: Heart rate variability, in-game behavior and self-report measures
2014
Assessing game experience by means of recordings of physiological reactions elicited during game play is a technique that has gained popularity in recent years in the field of digital games research. However, since physiological signals are typically linked to several psychological processes, the use of some measures such as cardiac activity or heart rate (HR) remains problematic. The goal of the present study is to investigate to what extent game logs and self-report measures of game experience have a predictive value for heart rate variability during game play. Our results showed that the accurate registration of in-game behaviors by means of game logs carries the potential of providing r…
A Stochastic Algorithm Based on Fast Marching for Automatic Capacitance Extraction in Non-Manhattan Geometries
2014
WOS:000346854900026 (Nº de Acesso Web of Science) We present an algorithm for two- and three-dimensional capacitance analysis on multidielectric integrated circuits of arbitrary geometry. Our algorithm is stochastic in nature and as such fully parallelizable. It is intended to extract capacitance entries directly from a pixelized representation of the integrated circuit (IC), which can be produced from a scanning electron microscopy image. Preprocessing and monitoring of the capacitance calculation are kept to a minimum, thanks to the use of distance maps automatically generated with a fast marching technique. Numerical validation of the algorithm shows that the systematic error of the algo…
H.264 QoS and Application Performance with Different Streaming Protocols
2015
Streaming techniques, including the selected streaming protocol, have an effect on the streaming quality. In this study, the performance of three different streaming protocols in a disturbed communication channel is evaluated with a modified version of the FFPlay player. A H.264 encoded video is used as a test sequence. The number of displayed image frames, the frame rate and playout duration are used as objective metrics for QoS. The metrics brings out differences of streaming protocols in our test environment. They are measured at the application level and have a connection to the user experience. peerReviewed
A Serendipity-Oriented Greedy Algorithm for Recommendations
2017
Most recommender systems suggest items to a user that are popular among all users and similar to items the user usually consumes. As a result, a user receives recommendations that she/he is already familiar with or would find anyway, leading to low satisfaction. To overcome this problem, a recommender system should suggest novel, relevant and unexpected, i.e. serendipitous items. In this paper, we propose a serendipity-oriented algorithm, which improves serendipity through feature diversification and helps overcome the overspecialization problem. To evaluate our algorithm and compare it with others, we employ a serendipity metric that captures each component of serendipity, unlike the most …
A DFT Study of Linear Gold–Thiolate Superclusters Absorbing in the Therapeutic NIR Window
2015
A series of linear clusters up to an aspect ratio of 1:6, formed as multimers of smaller clusters with an icosahedral Au13(5+) core having an eight-electron superatom configuration, are computationally predicted to have a greatly enhanced size-dependent absorption in the near-infrared (NIR) region extending to the biologically important NIR window. A novel structural model is presented for the previously isolated thiol-stabilized Au54(SR)30 cluster, where the metal core is formed as a heterodimer of the cores of the known Au25(SR)18(-/0) and Au38(SR)24 clusters.
Performance of an asymmetric and asynchronous decode-and-forward FBMC relay system
2014
End-to-end link performance of an asymmetric and asynchronous dual-hop decode-and-forward (DF) relay system built up using a causal multirate filter bank multicarrier (FBMC) technique operated under Rayleigh fading is presented. Three main performance measures namely bit error rate (BER), outage probability and channel capacity are used for this evaluation and approximate closed-form expressions for them are also made available. FBMC setup is modeled in exact form without any approximations while customizing to one of the most efficient subcarrier filter. Simulations are carried out in quasi-static multipath fading channels under symmetric, asymmetric, synchronous and asynchronous condition…
Long-range spin accumulation from heat injection in mesoscopic superconductors with Zeeman splitting
2015
Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).
Iron and pH regulating the photochemical mineralization of dissolved organic carbon
2017
Solar radiation mineralizes dissolved organic matter (DOM) to dissolved inorganic carbon through photochemical reactions (DIC photoproduction) that are influenced by iron (Fe) and pH. This study addressed as to what extent Fe contributes to the optical properties of the chromophoric DOM (CDOM) and DIC photoproduction at different pH values. We created the associations of Fe and DOM (Fe-DOM) that cover the range of loadings of Fe on DOM and pH values found in freshwaters. The introduced Fe enhanced the light absorption by CDOM independent of pH. Simulated solar irradiation decreased the light absorption by CDOM (i.e., caused photobleaching). Fe raised the rate of photobleaching and steepened…