Hydrogen‐bonding patterns and energetic profiles of acrylamide isomers (syn‐ and skew‐), tautomers (amide and imidic acid forms) and 13 stable dimers have been studied using the second‐order Møller–Plesset perturbation theory with basis sets up to aug‐cc‐pVTZ. Syn‐acrylamide is the most stable monomer with a reaction barrier of 4.15 kcal/mol for the syn–skew isomerization reaction. The direct amide–imidic acid tautomerization reaction is separated by too high a barrier to surpass. The most stable dimer corresponds to the planar double‐hydrogen‐bonded configuration, indicating its crucial role in determining the stability of the formed complex. Moreover, hydrogen bonds have significant effects on the infrared spectral features, which can be consistently explained solely based on the acrylamide dimeric structures and energetics without monomeric and dimeric tautomer forms. The results are useful for studying the stability of the acrylamide clusters in condensed‐phase samples such as those in food chemistry studies.

The explosive growth of uploaded photos requires service providers to improve the overall efficiency for analyzing and manipulating uploaded photos. Seeing the needs, we investigate the feasibility to speed up photo-related analysis (e.g., face detection) by leveraging the observations from largescale consumer photos. To deal with the huge computations of face detection on the large-scale photos, we aim to reduce search hypotheses (i.e., subwindows) for face detectors by thresholding (or ranking) on the confidence of hypothesis that indicates the possibility to be a face. Unlike the traditional sliding window which views all the hypotheses equally, prior knowledge of face sizes and locations in images is learned from the large-scale consumer photos, and used to model the confidence of each hypothesis. By thresholding on the ranked hypotheses, less likely hypotheses can be reduced for better efficiency. Our experiment demonstrates that 40% subwindows can be skipped while maintaining 95% face recall, compared to traditional sliding-windowbased methods.

Intermolecular interaction potentials of the acrylamide dimer in 12 equilibrium configurations have been calculated using the second-order Møller-Plesset (MP2) perturbation theory. We have employed Pople's medium size basis sets [up to 6-311++G(3df,2p)] and Dunning's correlation consistent basis sets (up to aug-cc-pVTZ). We have also carried out density functional theory (DFT) type calculations and compared the results with those calculated with the MP2 theory.