Software for Wearable Devices: Challenges and Opportunities

Wearable devices are a new form of mobile computer system that provides exclusive and user-personalized services. Wearable devices bring new issues and challenges to computer science and technology. This paper summarizes the development process and the categories of wearable devices. In addition, we present new key issues arising in aspects of wearable devices, including operating systems, database management system, network communication protocol, application development platform, privacy and security, energy consumption, human-computer interaction, software engineering, and big data.Comment: 6 pages, 1 figure, for Compsac 201

The hierarchy of higher order solutions of the derivative nonlinear Schr\"odinger equation

In this paper, we provide a simple method to generate higher order position solutions and rogue wave solutions for the derivative nonlinear Schr\"odinger equation. The formulae of these higher order solutions are given in terms of determinants. The dynamics and structures of solutions generated by this method are studied

The higher order Rogue Wave solutions of the Gerdjikov-Ivanov equation

We construct higher order rogue wave solutions for the Gerdjikov-Ivanov equation explicitly in term of determinant expression. Dynamics of both soliton and non-soliton solutions is discussed. A family of solutions with distinct structures are presented, which are new to the Gerdjikov-Ivanov equation

Decoding and Reprogramming Fungal Iterative Nonribosomal Peptide Synthetases

Nonribosomal peptide synthetases (NRPSs) assemble a large group of structurally and functionally diverse natural products. While the iterative catalytic mechanism of bacterial NRPSs is known, it remains unclear how fungal NRPSs create products of desired length. Here we show that fungal iterative NRPSs adopt an alternate incorporation strategy. Beauvericin and bassianolide synthetases have the same C1-A1-T1-C2-A2-MT-T2a-T2b-C3 domain organization. During catalysis, C3 and C2 take turns to incorporate the two biosynthetic precursors into the growing depsipeptide chain that swings between T1 and T2a/T2b with C3 cyclizing the chain when it reaches the full length. We reconstruct the total biosynthesis of beauvericin in vitro by reacting C2 and C3 with two SNAC-linked precursors and present a domain swapping approach to reprogramming these enzymes for peptides with altered lengths. These findings highlight the difference between bacterial and fungal NRPS mechanisms and provide a framework for the enzymatic synthesis of non-natural nonribosomal peptides

Get Tired of Socializing as Social Animal? An Empirical Explanation on Discontinuous Usage Behavior in Social Network Services

This research aims to explain users’ discontinuous usage behavior in social network context. With system features increasing, information flooding and personal network expanding of SNSs, users begin to emerge social network fatigue, and ultimately induce discontinuous usage intention. To explain this phenomenon, we develop a research model based on a cognition-affection-conation framework. This study examines the role of perceived overload (in terms of system feature overload, information overload and social overload) in influencing users’ negative affections of SNSs including social network fatigue and dissatisfaction, and the effects of such emotions on users’ discontinuous intention, which are validated through an empirical survey. The findings of this study contribute to a better understanding of the relationship among perceived overload, social network fatigue and users’ discontinuous usage behavior, and give some implications to SNSs providers to improve this situation

Understanding Why Fiscal Stimulus Can Fail through the Lens of the Survey of Professional Forecasters

This paper shows that fiscal policy in the U.S. has become ineffective due to lack of coordination between monetary and fiscal policy. We present a New Keynesian model that generates strong output effects of government spending shocks only when monetary policy coordinates well with fiscal policy. Employing the post-war U.S. data, we report strong stimulus effects of fiscal policy during the pre-Volcker era, which rapidly dissipate when we shift the sample period to the post-Volcker era. Finding a negligible role of the real interest rate in the propagation of government spending shocks, we propose an alternative explanation using a consumer sentiment channel. Employing the Survey of Professional Forecasters data, we show that forecasters tend to systematically over-estimate real GDP growth in response to positive innovations in government spending when policies coordinate well with each other. On the other hand, they are likely to formulate pessimistic forecasts when the monetary authority maintains a hawkish stance that conflicts with the fiscal stimulus. The fiscal stimulus, under such circumstances, may generate consumer pessimism, which decreases private spending and ultimately weakens the output effects of fiscal policy. We also provide statistical evidence that confirms an important role of the sentiment channel under different regimes of policy coordination

A redox conjugated polymer-based all-solid-state reference electrode

This work reports the design, synthesis, and characterization of a novel redox-active conjugated polyaniline containing quinone moiety as a solid state reference electrode. The union of electro-active quinone with π-conjugated polyaniline was created by the first chemical synthesis of para-dimethoxybenzene-functionalized aniline as a monomer using a palladium-mediated coupling. The successful polymerization of the as-prepared monomer was accomplished without acid additives. Its post-polymerization modification with strong Lewis acid boron tribromide furnished unique poly (aniline quinone/hydroquinone) with desired properties for all-solid-state reference electrode (RE) applications. The electrochemical responses from the conjugated polyaniline backbone in this unique polymer have been “suppressed” by the quinone pendant. The resulting poly (aniline quinone) showed a quasi-reversible redox process from the redox behavior of the pendant quinone. The stable electrode potential of this poly (aniline quinone/hydroquinone) suggested that it was a single phase in which the amounts of totally reduced and totally oxidized species could be maintained at a constant in various solvents and electrolytes. Its electrochemical stability was excellent with 95% peak current retention after continuous cyclic voltammetric testing. The aniline and quinone moieties in poly (aniline quinone/hydroquinone) render it to have both hydrophilic and hydrophobic compatibility. It showed excellent behavior as a reference electrode in aqueous and non-aqueous media and can be used in both non-zero current and zero-current conditions, providing a stable potential with a maximum potential drift of ~4.7 mV over ten consecutive days

Effect of Impeller Inlet Geometry on Cavitation Performance of Centrifugal Pumps Based on Radial Basis Function

Aiming at the cavitation problem, the blade leading edge shape has been changed to analyze its impact on the cavitation performance for centrifugal pumps. And the response model has been established based on the Radial Basis Function. The calculation case results show that the leading edge extending forward along the shroud can improve the inlet flow condition and cavitation performance. But the cavitation performance has been reduced immensely when the leading edge extends backward along the shroud. Along with the leading edge which extends forward along the hub, the cavitation performance increases at first and then decreases. A better cavitation performance for centrifugal pumps has lower load of blade inlet and higher pressure of blade suction side. The pressure pulsation is affected by the vortex out of the impeller and the falling-off and collapsing of the cavitation bubbles. The lower the pressure pulsation for blade passing frequency and the second harmonics of the samples is, the better the cavitation performance is. A relatively accurate response model based on the Radial Basis Function has been established to predict the effect of the shape of blade leading edge on the cavitation performance of centrifugal pumps