Crowdsourcing to Smartphones: Incentive Mechanism Design for Mobile Phone Sensing

Mobile phone sensing is a new paradigm which takes advantage of the pervasive smartphones to collect and analyze data beyond the scale of what was previously possible. In a mobile phone sensing system, the platform recruits smartphone users to provide sensing service. Existing mobile phone sensing applications and systems lack good incentive mechanisms that can attract more user participation. To address this issue, we design incentive mechanisms for mobile phone sensing. We consider two system models: the platform-centric model where the platform provides a reward shared by participating users, and the user-centric model where users have more control over the payment they will receive. For the platform-centric model, we design an incentive mechanism using a Stackelberg game, where the platform is the leader while the users are the followers. We show how to compute the unique Stackelberg Equilibrium, at which the utility of the platform is maximized, and none of the users can improve its utility by unilaterally deviating from its current strategy. For the user-centric model, we design an auction-based incentive mechanism, which is computationally efficient, individually rational, profitable, and truthful. Through extensive simulations, we evaluate the performance and validate the theoretical properties of our incentive mechanisms

2-Hydroxy­benzoic acid–purin-6-amine (3/1)

In the title 3:1 adduct, 3C7H6O3·C5H5N5, an intra­molecular O—H⋯O hydrogen bond occurs in each of the three 2-hydroxy­benzoic acid mol­ecules. In the crystal, the components are linked by N—H⋯O and O—H⋯N hydrogen bonds

Enhanced stability of Zr-doped Ba(CeTb)O3−δ-Ni cermet membrane for hydrogen separation

A mixed protonic and electronic conductor material BaCe0.85Tb0.05Zr0.1O3−δ (BCTZ) is prepared and a Ni-BCTZ cermet membrane is synthesized for hydrogen separation. Stable hydrogen permeation fluxes can be obtained for over 100 h through the Ni-BCTZ membrane in both dry and humid conditions, which exhibits an excellent stability compared with Ni-BaCe0.95Tb0.05O3−δ membrane due to the Zr doping.Sino-German center for Science Promotion/GZ 911National Science Foundation of China/21225625National Science Foundation of China/2117608

3-(4-Amino-5-thioxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)pyridinium chloride

In the title compound, C7H8N5S+·Cl−, the dihedral angle formed by the pyridine ring with the triazole ring is 10.0 (1)°. There are weak inter­molecular hydrogen-bond inter­actions in the crystal structure, involving the NH and NH2 groups as donors, and the chloride anion, the S atom in the thio­ketone group and the unsubstituted ring N atom as acceptors

One-shot ultraspectral imaging with reconfigurable metasurfaces

One-shot spectral imaging that can obtain spectral information from thousands of different points in space at one time has always been difficult to achieve. Its realization makes it possible to get spatial real-time dynamic spectral information, which is extremely important for both fundamental scientific research and various practical applications. In this study, a one-shot ultraspectral imaging device fitting thousands of micro-spectrometers (6336 pixels) on a chip no larger than 0.5 cm$^2$, is proposed and demonstrated. Exotic light modulation is achieved by using a unique reconfigurable metasurface supercell with 158400 metasurface units, which enables 6336 micro-spectrometers with dynamic image-adaptive performances to simultaneously guarantee the density of spectral pixels and the quality of spectral reconstruction. Additionally, by constructing a new algorithm based on compressive sensing, the snapshot device can reconstruct ultraspectral imaging information ($\Delta\lambda$/$\lambda$~0.001) covering a broad (300-nm-wide) visible spectrum with an ultra-high center-wavelength accuracy of 0.04-nm standard deviation and spectral resolution of 0.8 nm. This scheme of reconfigurable metasurfaces makes the device can be directly extended to almost any commercial camera with different spectral bands to seamlessly switch the information between image and spectral image, and will open up a new space for the application of spectral analysis combining with image recognition and intellisense

Collapse and reappearance of magnetic orderings in spin frustrated TbMnO3 induced by Fe substitution

We studied the temperature dependent magnetic phase evolution in spin frustrated TbMnO3 affected by Fe doping via powder neutron diffraction. With the introduction of Fe (10% and 20%), the long range incommensurate magnetic orderings collapse. When the Fe content is increased to 30%, a long-range antiferromagnetic ordering develops, while a spin reorientation transition is found near 35 K from a canted G-type antiferromagnetic ordering to a collinear G-type antiferromagnetic ordering. This work demonstrates the complex magnetic interactions existing in transition metal oxides, which helps to understand the frustrated spin states in other similar systems and design magnetic materials as well

Ethyl (E)-3-anilino-2-cyano-3-mercaptoacrylate

In the title compound, C12H12N2O2S, there are S—H⋯N and N—H⋯O hydrogen-bond inter­actions. The N—H⋯O hydrogen bond is bifurcated, with the hydrogen being simultaneously donated to two equivalent O atoms, forming one intra- and one inter­molecular N—H⋯O bond with an R 1 2(4) motif. The motif of the S—H⋯N hydrogen bond is R 2 2(12)