A Study Of Virtuous Cycle Of Service Participation On Crowdsourcing Platforms

Competition has undoubtedly increased substantially over the last decade for several reasons. The Internet has been far and away the largest contributor to the rise in competitive markets due to establishing an online business has lower operating costs and greater flexibility. Companies must have internet business ideas to survive to stay competitive in today’s markets. Crowdsourcing is a phenomenon receiving highly attention both inside and outside of academia. With the rapid development of Web2.0 and social media, an emerging business model like a raging fire impacts on the market: a crowdsourcing platform. Crowdsourcing platforms provide a good environment to fulfill people’s needs and seize value from providing products and services. It is important to understand what drives people to deliver and capture values from a crowdsourcing platform. The purpose of this paper is to explore how service participation works on successful crowdsourcing platforms in their cycles. We focus on why do participants (both sides of supply and demand) are willing to join into the platform to provide services and request services, finding out their virtuous cycles on the platforms in different applications. This study is the first of its kind to explore how service participation works on successful crowdsourcing platforms in their cycles. We will use a qualitative multiple case study, which facilitated an exploration of the phenomenon in an area that has received little theoretical development and allowed us to study the cycle of service participation on crowdsourcing platform in a real-life context. The results may reveal us some significant driving factors on why people are willing to provide and request services on crowdsourcing platforms and what important strategies should be taken while running a crowdsourcing platform. This not only gives us a more broaden view of crowdsourcing and platform operating, but also provides companies, which use crowdsourcing platform to run their business, a more realistic decision making references

Spatial inefficiency of MaxWeight scheduling

MaxWeight scheduling has gained enormous popularity as a powerful paradigm for achieving queue stability and maximum throughput in a wide variety of scenarios. The maximum-stability guarantees however rely on the fundamental premise that the system consists of a fixed set of flows with stationary ergodic traffic processes. In the present paper we examine networks where the population of active flows varies over time, as flows eventually end while new flows occasionally start. We show that MaxWeight policies may fail to provide maximum stability due to persistent inefficient spatial reuse. The intuitive explanation is that these policies tend to serve flows with large backlogs, even when the resulting spatial reuse is not particularly efficient, and fail to exploit maximum spatial reuse patterns involving flows with smaller backlogs. These results indicate that instability of MaxWeight scheduling can occur due to spatial inefficiency in networks with fixed transmission rates, which is fundamentally different from the inability to fully exploit time-varying rates shown in prior work. We discuss how the potential instability effects can be countered by spatial traffic aggregation, and describe some of the associated challenges and performance trade-offs

Diffusion on a stepped substrate

We present results for collective diffusion of adatoms on a stepped substrate with a submonolayer coverage. We study the combined effect of the additional binding at step edge, the Schwoebel barrier, the enhanced diffusion along step edges, and the finite coverage on diffusion as a function of step density. In particular, we examine the crossover from step--dominated diffusion at high step density to terrace-dominated behavior at low step density in a lattice-gas model using analytical Green's function techniques and Monte Carlo simulations. The influence of steps on diffusion is shown to be more pronounced than previously anticipated.Comment: 4 pages, RevTeX, 3 Postscript figure

A Wideband Triple-Mode Differentially-Fed Microstrip Patch Antenna

© 2021 IEEE. This is the accepted manuscript version of an article which has been published in final form at https://dx.doi.org/10.1109/LAWP.2021.3074302A wideband differentially-fed microstrip patch antenna (MPA) with tripe-resonant modes is presented in this letter. The proposed triple-mode MPA is realized by combining two dual-mode MPAs (MPA-I and MPA-II) with different resonant frequency ratios. Firstly, the TM0,1 mode and TM0,1/2 mode of dual-mode MPA-I can be concurrently excited by adding a pair of coupling shorted patches beside the strip MPA. The ratio of f0,1/2/f0,1 can be easily adjusted by moving the shorting pins between the strip MPA and shorted patches. Secondly, by properly designing the dimensions of a conventional MPA, the TM0,1 and TM2,1 modes of dual-mode MPA-II are simultaneously excited. To further reduce the ratio of f2,1/f0,1, four slots are elaborately etched on the conventional MPA. Finally, by combining the two dual-mode MPAs, a triple-mode MPA with the frequency ratio of f0,1/2:f2,1:f0,1 = 1.2:1.1:1 is realized. To verify the design concept, a prototype of triple-mode MPA was fabricated and measured. Experimental results show that the proposed microstrip antenna achieves a wide bandwidth of 26.5%, a low cross-polarization of -23 dB, and high harmonic suppression.Peer reviewe

Non-equilibrium surface diffusion in the O/W(110) system

In this Letter, we present results of an extensive Monte Carlo study of the O/W(110) system under non-equilibrium conditions. We study the mean square displacements and long wavelength density fluctuations of adatoms. From these quantities, we define effective and time-dependent values for the collective and tracer diffusion mobilities. These mobilities reduce to the usual diffusion constants when equilibrium is reached. We discuss our results in view of existing experimental measurements of effective diffusion barriers, and the difficulties associated with interpreting non-equilibrium data.Comment: 14 pages LaTeX and five PostScript figures; tarred, gzip'ed, and uuencoded. Uses elsart.sty and elsart12.sty which are included in the package. To appear in Surface Science Letter

Commensurate-incommensurate transition and domain wall dynamics of adsorbed overlayers on a honeycomb substrate

© EPLA, 2016.We introduce an effective one-mode phase-field crystal model for studying the commensurate-incommensurate transition and domain wall dynamics of the ( √ 3×√3)R30 phase found in systems such as Xe/Pt(111), or Xe and Kr on graphite. The model allows us to study large systems where the domain walls can be separated over large macroscopic distances and at the same time incorporate the microscopic details of the domain wall structures. The resulting phase diagram shows that an intermediate stripe incommensurate phase always separates the commensurate phase from the honeycomb incommensurate phases. The energy of the domain wall crossing is investigated. We also find that near a step edge, the domain walls tend to align perpendicularly to the step edge, in agreement with recent experimental observations

Striped, honeycomb, and twisted moire patterns in surface adsorption systems with highly degenerate commensurate ground states

Atomistically thin adsorbate layers on surfaces with a lattice mismatch display complex spatial patterns and ordering due to strain-driven self-organization. In this work, a general formalism to model such ultrathin adsorption layers that properly takes into account the competition between strain and adhesion energy of the layers is presented. The model is based on the amplitude expansion of the two-dimensional phase field crystal (PFC) model, which retains atomistic length scales but allows relaxation of the layers at diffusive time scales. The specific systems considered here include cases where both the film and the adsorption potential can have either honeycomb (H) or triangular (T) symmetry. These systems include the so-called (1 × 1), (√3 × √3) R30∘, (2 × 2), (√7 × √7) R19.1∘, and other higher order states that can contain a multitude of degenerate commensurate ground states. The relevant phase diagrams for many combinations of the H and T systems are mapped out as a function of adhesion strength and misfit strain. The coarsening patterns in some of these systems is also examined. The predictions are in good agreement with existing experimental data for selected strained ultrathin adsorption layers

Translating online customer opinions into engineering characteristics in QFD: A probabilistic language analysis approach

Online opinions provide informative customer requirements for product designers. However, the increasing volume of opinions make them hard to be digested entirely. It is expected to translate online opinions for designers automatically when they are launching a new product. In this research, an exploratory study is conducted, in which customer requirements in online reviews are manually translated into engineering characteristics (ECs) for Quality function deployment (QFD). From the exploratory study, a simple mapping from keywords to ECs is observed not able to be built. It is also found that it will be a time-consuming task to translate a large number of reviews. Accordingly, a probabilistic language analysis approach is proposed, which translates reviews into ECs automatically. In particular, the statistic concurrence information between keywords and nearby words is analyzed. Based on the unigram model and the bigram model, an integrated impact learning algorithm is advised to estimate the impacts of keywords and nearby words respectively. The estimated impacts are utilized to infer which ECs are implied in a given context. Using four brands of printer reviews from Amazon.com, comparative experiments are conducted. Finally, an illustrative example is shown to clarify how this approach can be applied by designers in QFD

A Dynamical Mean Field Theory for the Study of Surface Diffusion Constants

We present a combined analytical and numerical approach based on the Mori projection operator formalism and Monte Carlo simulations to study surface diffusion within the lattice-gas model. In the present theory, the average jump rate and the susceptibility factor appearing are evaluated through Monte Carlo simulations, while the memory functions are approximated by the known results for a Langmuir gas model. This leads to a dynamical mean field theory (DMF) for collective diffusion, while approximate correlation effects beyond DMF are included for tracer diffusion. We apply our formalism to three very different strongly interacting systems and compare the results of the new approach with those of usual Monte Carlo simulations. We find that the combined approach works very well for collective diffusion, whereas for tracer diffusion the influence of interactions on the memory effects is more prominent.Comment: 13 pages LaTeX and 6 PostScript figures, style files included. To appear in Surface Science Letter

Dynamics and Scaling of 2D Polymers in a Dilute Solution

The breakdown of dynamical scaling for a dilute polymer solution in 2D has been suggested by Shannon and Choy [Phys. Rev. Lett. {\bf 79}, 1455 (1997)]. However, we show here both numerically and analytically that dynamical scaling holds when the finite-size dependence of the relevant dynamical quantities is properly taken into account. We carry out large-scale simulations in 2D for a polymer chain in a good solvent with full hydrodynamic interactions to verify dynamical scaling. This is achieved by novel mesoscopic simulation techniques