A framework for personalized adaptive user interest prediction based on topic model and forgetting mechanism

User interest is not static and changes dynamically. In the scenario of a search engine, this paper presents a personalized adaptive user interest prediction framework. It represents user interest as a topic distribution, captures every change of user interest in the history, and uses the changes to predict future individual user interest dynamically. More specifically, it first uses a personalized user interest representation model to infer user interest from queries in the user’s history data using a topic model; then it presents a personalized user interest prediction model to capture the dynamic changes of user interest and to predict future user interest by leveraging the query submission time in the history data. Compared with the Interest Degree Multi-Stage Quantization Model, experiment results on an AOL Search Query Log query log show that our framework is more stable and effective in user interest prediction.     

Integrated heat and power dispatch model for wind-CHP system with solid heat storage device based on robust stochastic theory

This paper built a combined heat and power (CHP) dispatch model for wind-CHP system with solid heat storage device (SHS) aiming at minimizing system coal consumption, and set system demand-supply balance and units’ operation conditions as the operation constraints. Furthermore, robust stochastic optimization theory was used to describe wind power output uncertainty. The simulation result showed that SHS increased CHP peak-valley shifting capability and reduced abandoned wind rate from 12% to 6%, and reduced 5% coal consumption, compared with the original system operation by flexible charging electric power and heating. The payback period of employing SHS in wind-CHP system is far shorter than SHS expected service life.     

Generalized Intersection Bodies with Parameter

AIn 2005, the classical intersection bodies and L_p intersection bodies were extended. Afterwards, the concept of general L_p intersection bodies and the generalized intersection bodies was introduced. In this paper, we define the generalized bodies with parameter. Besides, we establish the extremal values for volume, Brunn-Minkowski type inequality for radial combination and L_p harmonic Blaschke combination of this notion.     

Global Existence and Optimal Decay Rate of the Compressible Magnetohydrodynamic Equation with Potential Force

In this paper, we consider the three dimensional compressible viscous magnetohydrodynamic equations(MHD) with the external potential force. We first derive the corresponding non-constant stationary solutions. Next, we show global wellposedness of the initial value problem for the three dimensional compressible viscous magnetohydrodynamic equations, provided that the initial data is close to the stationary solution. Finally, based on the elaborate energy estimates for the nonlinear system and L~p-L~q decay estimates of the linearized equation, we show the optimal convergence rates of the solution in L~q-norm with 2≤q≤6 and its first derivative in L~2-norm when the initial perturbation is bounded in L~p-norm with 1≤p6/5.     

Seasonal Variation and Land-Use/Land-Cover Type Impacts on the Correlation of Urban Heat Island Intensity and Difference Vegetation Index with Satellite Data in Xi’an,China

Green coverage has pronounced influences on urban heat island (UHI) effect, while the impacts of seasonal variation and Land-Use/Land-Cover (LULC) types on this effect has not been implemented. This paper investigated the spatio-seasonal characteristics of urban thermal environment and the vegetation-soil mixed area, and then explored the effects of vegetation status on UHI intensity from the perspectives of seasons and regions in Xi’an using four Landsat 8 images. UHI intensity index was implemented to extract UHI intensity based on thermal infrared imagery, and difference vegetation index (DVI) was used to represent vegetation-soil mixed area. Results indicated that DVI has impacts on UHI intensity, and their relations vary with season and region. In the whole Xi’an, if UHI intensity is smaller than -0.1, DVI increases with the increase of UHI intensity; whereas for UHI intensity is greater than -0.1, DVI decreases with increases of the UHI intensity from early spring to autumn. The highest correlation level was discovered in the autumn map (R²=0.713). Results of correlation analysis further displayed that DVI positively correlated with UHI intensity at impervious surface, and that the main urban area possessed the best correlation with R²=0.564 5.     

A Time-Domain Electromagnetic Transmitter with Great Power and Large Current by Using a Closed-Loop Phase Shifting Control Strategy

A time-domain electromagnetic transmitter (TDET) with great power and large current was designed by using a closed-loop phase shifting control strategy. A clamping voltage source circuit was applied in this system to improve the falling edge of emission current and shorten the turn-off time. The simulated results showed that this TDET exhibited the advantages including a large current, strong capability for rapid turn-off, stably output voltage, preferably dynamic performance, a widely adjustable range in transmitting voltage, accurate measurement precision.     

Fingerprint Core Location Algorithm Based on Sliding Window

In order to improve the efficiency of the fingerprint core location algorithm, a fingerprint core location method using sliding window on the basis of core location algorithm with the complex filter was proposed. The local region of the fingerprint image was extracted by a fixed-size window sliding in the region of the fingerprint image, and the selected local region by window as the calculation object is used to detect the core. The experiment results show that the method cannot only effectively detect fingerprint core, but also improve the efficiency of the detection algorithm comparing with the global fingerprint core location detection algorithm.     

Generation of Linear and Parabolic Concentration Gradients by Using a Christmas Tree-Shaped Microfluidic Network

This paper describes a simple method of generating concentration gradients with linear and parabolic profiles by using a Christmas tree-shaped microfluidic network.The microfluidic gradient generator consists of two parts:a Christmas tree-shaped network for gradient generation and a broad microchannel for detection.A two-dimensional model was built to analyze the flow field and the mass transfer in the microfluidic network.The simulating results show that a series of linear and parabolic gradient profiles were generated via adjusting relative flow rate ratios of the two source solutions(R_L~2≥0.995 and _PR~2≥0.999),which could match well with the experimental results(R_L~2≥0.987 and _PR~2≥0.996).The proposed method is promising for the generation of linear and parabolic concentration gradient profiles,with the potential in chemical and biological applications such as combinatorial chemistry synthesis,stem cell differentiation or cytotoxicity assays.     

Critical Chords of Convex Bodies of Constant Width

In this paper, we show that when Minkowski measure of asymmetry of convex body K of constant width is bigger than α (n-1), K has at least n+1 critical chords, where \(\alpha (n) = \frac{{n + \sqrt {2n(n + 1)} }}{{n + 2}}\).     

Wiener Indices in Random Cyclooctane Chains

The Wiener index of a connected graph (molecule graph) G is the sum of the distances between all pairs of vertices of G. In this paper, simple exact formula are established for the expected value of Wiener index in random cyclooctane chain. Moreover, we obtain the average value of the Wiener indices with respect to the set of all cyclooctane chains with n octagons.