On the Feature Discovery for App Usage Prediction in Smartphones

With the increasing number of mobile Apps developed, they are now closely integrated into daily life. In this paper, we develop a framework to predict mobile Apps that are most likely to be used regarding the current device status of a smartphone. Such an Apps usage prediction framework is a crucial prerequisite for fast App launching, intelligent user experience, and power management of smartphones. By analyzing real App usage log data, we discover two kinds of features: The Explicit Feature (EF) from sensing readings of built-in sensors, and the Implicit Feature (IF) from App usage relations. The IF feature is derived by constructing the proposed App Usage Graph (abbreviated as AUG) that models App usage transitions. In light of AUG, we are able to discover usage relations among Apps. Since users may have different usage behaviors on their smartphones, we further propose one personalized feature selection algorithm. We explore minimum description length (MDL) from the training data and select those features which need less length to describe the training data. The personalized feature selection can successfully reduce the log size and the prediction time. Finally, we adopt the kNN classification model to predict Apps usage. Note that through the features selected by the proposed personalized feature selection algorithm, we only need to keep these features, which in turn reduces the prediction time and avoids the curse of dimensionality when using the kNN classifier. We conduct a comprehensive experimental study based on a real mobile App usage dataset. The results demonstrate the effectiveness of the proposed framework and show the predictive capability for App usage prediction.Comment: 10 pages, 17 figures, ICDM 2013 short pape

Completion of codes with finite bi-decoding delays

AbstractLet A∗ be a free monoid generated by a set A and let X⊆A∗ be a code with property P. The embedding of X into a complete code Y⊆A∗ with the same property P is called the completion of X. The method of completion of rational bifix codes and codes with finite decoding delays have been investigated by a number of authors. In this paper, we provide a general method of construction for completing the codes with finite bi-decoding delays. As a consequence, the completion method of rational bifix codes and codes with finite decoding delays is extended and applied to codes with finite bi-decoding delays

H\to hh in the Mirror Model at the CERN Large Hadron Collider

The Higgs sector may play an important role in detecting the mirror particles, which can be the candidates of the dark matter and appear as missing energy in the detectors at the LHC. In this paper we worked out the Higgs boson spectrum and the Higgs couplings for the symmetric vacuum, namely $v_1=v_2=v$, in the mirror model, and investigated the constraints from electro-weak precision observable (EWPO). Our study showed that the EWPO has already constrained the Higgs boson sector severely. We then explored the Higgs boson phenomenology, and focused on the scenario that the heavier Higgs boson $H$ can decay into a pair of lighter Higgs boson $h$. We proposed to study the invisible decay of the Higgs boson via the pair production of them, in which one Higgs boson decays into bottom quarks and the other decays invisibly. Our detail simulation for signals and backgrounds showed that the observation of signal can reach $5\sigma$ significance for $m_H=260$ GeV and $m_h=115$ GeV with $10 fb^{-1}$integrated luminosity at the LHC. Moreover the possible method to further suppress dominant $Zb\bar{b}$ background was discussed. We also simulated the signals and backgrounds for $H \to h h \to 4b$. Our results showed that it is very difficult to isolate the signals from huge QCD continuum backgrounds.Comment: 9 pages, revtex4, typo correcte

A Phase Change Storage Material that May be Used in the Fire Resistance of Building Structure

AbstractThis study prepared polyethylene glycol/silicon dioxide composite, a kind of form-stable phase change material. The composites can be made into mortar which is able to adhere to the surface of building structure and absorb the fire heat. This paper aims to study the effect of the composites on the fire resistance of building structure. Scanning electronic microscope and differential scanning calorimeter were adopted to investigate the structural and thermal properties of the composites. It was found that the polyethylene glycol was well dispersed into the network of solid SiO2. And the latent heat of PEG/SiO2 increased with the decrease of SiO2 content. The required weight percentage of SiO2 was found to be 15% at least if the composites remain solid without leakage. It was also found that a phase change of pure PEG6000 happened with an enthalpy of 158J/g while the 80 wt% PEG composite is 133J/g. In conclusion, the phase change storage material may be used for fire resistance of building structure

4-(4-Nitro­benzene­sulfonamido)pyridinium trichloro­acetate

In the crystal structure of the title compound, C11H10N3O4S·C2Cl3O2, the dihedral angle between the two six-membered rings is 69.2 (1)°. The mol­ecules are connected via inter­molecular N—H⋯O hydrogen bonding