10,230 research outputs found

    Integrating guanxi into technology acceptance: an empirical investigation of WeChat

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    Social influence is an important research topic in the technology acceptance literature, in particular for social media. Prior empirical studies have for the most part employed social influence theory to investigate user intentions to continue with social media, while culture driven theories have been neglected. Rather than using social influence theory, we introduced guanxi theory to explore how guanxi social mechanisms (or processes) influence Chinese users’ continuance intentions in WeChat. Specifically, we developed a model that examines the role of guanxi as manifested by renqing, mianzi and ganqing in perceived usefulness, perceived enjoyment and continuance intention in WeChat. A survey research method was adopted to test the proposed hypotheses. This study found that ganqing has a positive impact on perceived usefulness and continuance intention. Mianzi exerts a negative effect on continuance intention but exhibits a positive effect on perceived usefulness. Renqing was found to have no significant impact on perceived usefulness and continuance intention. Our study advances the Technology Acceptance Model (TAM) by introducing guanxi-based constructs in a Chinese mobile social-messaging application context. Our study also offers alternative insights on guanxi-based social influence processes in the Chinese technology acceptance literature

    Multivariate Anisotropic Interpolation on the Torus

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    We investigate the error of periodic interpolation, when sampling a function on an arbitrary pattern on the torus. We generalize the periodic Strang-Fix conditions to an anisotropic setting and provide an upper bound for the error of interpolation. These conditions and the investigation of the error especially take different levels of smoothness along certain directions into account

    Electronic Structure of LuRh2Si2: "Small" Fermi Surface Reference to YbRh2Si2

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    We present band structure calculations and quantum oscillation measurements on LuRh2Si2, which is an ideal reference to the intensively studied quantum critical heavy-fermion system YbRh2Si2. Our band structure calculations show a strong sensitivity of the Fermi surface on the position of the silicon atoms zSi within the unit cell. Single crystal structure refinement and comparison of predicted and observed quantum oscillation frequencies and masses yield zSi = 0.379c in good agreement with numerical lattice relaxation. This value of zSi is suggested for future band structure calculations on LuRh2Si2 and YbRh2Si2. LuRh2Si2 with a full f electron shell represents the "small" Fermi surface configuration of YbRh2Si2. Our experimentally and ab initio derived quantum oscillation frequencies of LuRh2Si2 show strong differences with earlier measurements on YbRh2Si2. Consequently, our results confirm the contribution of the f electrons to the Fermi surface of YbRh2Si2 at high magnetic fields. Yet the limited agreement with refined fully itinerant local density approximation calculations highlights the need for more elaborated models to describe the Fermi surface of YbRh2Si2.Comment: 12 pages 10 figure

    Congestion and centrality in traffic flow on complex networks

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    The central points of communication network flow has often been identified using graph theoretical centrality measures. In real networks, the state of traffic density arises from an interplay between the dynamics of the flow and the underlying network structure. In this work we investigate the relationship between centrality measures and the density of traffic for some simple particle hopping models on networks with emerging scale-free degree distributions. We also study how the speed of the dynamics are affected by the underlying network structure. Among other conclusions, we find that, even at low traffic densities, the dynamical measure of traffic density (the occupation ratio) has a non-trivial dependence on the static centrality (quantified by "betweenness centrality"), which non-central vertices getting a comparatively large portion of the traffic.Comment: To appear in Advances in Complex System

    Fairness Beyond Disparate Treatment & Disparate Impact: Learning Classification without Disparate Mistreatment

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    Automated data-driven decision making systems are increasingly being used to assist, or even replace humans in many settings. These systems function by learning from historical decisions, often taken by humans. In order to maximize the utility of these systems (or, classifiers), their training involves minimizing the errors (or, misclassifications) over the given historical data. However, it is quite possible that the optimally trained classifier makes decisions for people belonging to different social groups with different misclassification rates (e.g., misclassification rates for females are higher than for males), thereby placing these groups at an unfair disadvantage. To account for and avoid such unfairness, in this paper, we introduce a new notion of unfairness, disparate mistreatment, which is defined in terms of misclassification rates. We then propose intuitive measures of disparate mistreatment for decision boundary-based classifiers, which can be easily incorporated into their formulation as convex-concave constraints. Experiments on synthetic as well as real world datasets show that our methodology is effective at avoiding disparate mistreatment, often at a small cost in terms of accuracy.Comment: To appear in Proceedings of the 26th International World Wide Web Conference (WWW), 2017. Code available at: https://github.com/mbilalzafar/fair-classificatio

    An SO(10) Grand Unified Theory of Flavor

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    We present a supersymmetric SO(10) grand unified theory (GUT) of flavor based on an S4S_4 family symmetry. It makes use of our recent proposal to use SO(10) with type II seesaw mechanism for neutrino masses combined with a simple ansatz that the dominant Yukawa matrix (the {\bf 10}-Higgs coupling to matter) has rank one. In this paper, we show how the rank one model can arise within some plausible assumptions as an effective field theory from vectorlike {\bf 16} dimensional matter fields with masses above the GUT scale. In order to obtain the desired fermion flavor texture we use S4S_4 flavon multiplets which acquire vevs in the ground state of the theory. By supplementing the S4S_4 theory with an additional discrete symmetry, we find that the flavon vacuum field alignments take a discrete set of values provided some of the higher dimensional couplings are small. Choosing a particular set of these vacuum alignments appears to lead to an unified understanding of observed quark-lepton flavor: (i) the lepton mixing matrix that is dominantly tri-bi-maximal with small corrections related to quark mixings; (ii) quark lepton mass relations at GUT scale: mbmτm_b\simeq m_{\tau} and mμ3msm_\mu\simeq 3 m_s and (iii) the solar to atmospheric neutrino mass ratio m/matmθCabibbom_\odot/m_{\rm atm}\simeq \theta_{\rm Cabibbo} in agreement with observations. The model predicts the neutrino mixing parameter, Ue3θCabibbo/(32)0.05U_{e3} \simeq \theta_{\rm Cabibbo}/(3\sqrt2) \sim 0.05, which should be observable in planned long baseline experiments.Comment: Final version of the paper as it will appear in JHEP

    Open-ended evolution to discover analogue circuits for beyond conventional applications

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10710-012-9163-8. Copyright @ Springer 2012.Analogue circuits synthesised by means of open-ended evolutionary algorithms often have unconventional designs. However, these circuits are typically highly compact, and the general nature of the evolutionary search methodology allows such designs to be used in many applications. Previous work on the evolutionary design of analogue circuits has focused on circuits that lie well within analogue application domain. In contrast, our paper considers the evolution of analogue circuits that are usually synthesised in digital logic. We have developed four computational circuits, two voltage distributor circuits and a time interval metre circuit. The approach, despite its simplicity, succeeds over the design tasks owing to the employment of substructure reuse and incremental evolution. Our findings expand the range of applications that are considered suitable for evolutionary electronics

    A Comparison of Perceptions of Knowledge and Skills Held by Primary and Secondary Teachers: From the Entry to Exit of Their Preservice Programme

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    The purpose of this study was to investigate if there were differences in the levels of pedagogical knowledge and skills as perceived by the student teachers who were enrolled in the Primary and the Secondary Post Graduate Diploma in Education programme at the National Institute of Education in Singapore. 170 Primary and 426 Secondary student teachers participated in the study. The results showed that there were no significant differences at the beginning of the programme between the two cohorts. However, there were significant differences between the two groups at the end of programme, with the Primary student teachers tending to perceive themselves as gaining more pedagogical knowledge and skills by the end of their initial teacher preparation programme than the Secondary student teachers

    Tailoring the surface properties of carbon nitride incorporated thin film nanocomposite membrane for forward osmosis desalination

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    Thin film nanocomposite (TFN) membranes incorporated with carbon nitride (CN) or protonated CN (pCN) were fabricated for forward osmosis (FO) desalination. The CN and pCN were incorporated within the polyamide (PA) layer which was supported by pCN incorporated polysulfone (PSf) substrate to form the TFN membrane. It was found that the presence of pCN in the substrate has favourably altered the intrinsic properties and affected the formation of PA layer. The physico-chemical characterizations indicated that the presence of both CN and pCN enhanced the surface hydrophilicity but reduced the surface negativity of the PA layer. These features have resulted in the improved water transport and salt rejective ability. As a result, CN-pCN-TFN membranes exhibited improved water permeability by about 70% (0.67 L/m2 h bar) compared to TFC membrane while maintaining salt rejection of 94.5%. CN-pCN-TFN also exhibited better anti-fouling property compared to TFC in which the flux decline was only half of that of TFC membrane during the 9 -h antifouling test. This work demonstrates the feasibility of using functional CN and pCN to independently tailor the substrate and PA layer properties of the TFN membrane, hence improving the desalination performances of the membrane
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