Analysis on Human Blockage Path Loss and Shadow Fading in Millimeter-Wave Band

Millimeter-wave (Mm-w) is the trend of communication development in the future; users who carry mobile communication equipment could be blocked by others in a crowded population environment. Based on Shooting and Bouncing Ray (SBR) method and setting up different orientation receivers (RX), population density, and people fabric property at 28 GHz and 38 GHz, simulating experimental scene similar to station square by Wireless Insite software, we use least square method to do linear-regression analysis for path loss and build path loss model. The result shows that the path loss index has a certain change in the different frequency, orientation receivers, population density, and people fabric. The path loss index of RouteC1 and RouteA2 has an obvious change in the central transmitter (TX). Each route shadow fading obeys Gaussian distribution whose mean is 0. This paper’s result has a theoretical guiding for designing the communication system in a crowded population environment

Stereo Event-based Visual-Inertial Odometry

Event-based cameras are new type vision sensors whose pixels work independently and respond asynchronously to brightness change with microsecond resolution, instead of providing standard intensity frames. Compared with traditional cameras, event-based cameras have low latency, no motion blur, and high dynamic range (HDR), which provide possibilities for robots to deal with some challenging scenes. We propose a visual-inertial odometry for stereo event-based cameras based on Error-State Kalman Filter (ESKF). The visual module updates the pose relies on the edge alignment of a semi-dense 3D map to a 2D image, and the IMU module updates pose by median integral. We evaluate our method on public datasets with general 6-DoF motion and compare the results against ground truth. We show that our proposed pipeline provides improved accuracy over the result of the state-of-the-art visual odometry for stereo event-based cameras, while running in real-time on a standard CPU (low-resolution cameras). To the best of our knowledge, this is the first published visual-inertial odometry for stereo event-based cameras

A User-Centered Concept Mining System for Query and Document Understanding at Tencent

Concepts embody the knowledge of the world and facilitate the cognitive processes of human beings. Mining concepts from web documents and constructing the corresponding taxonomy are core research problems in text understanding and support many downstream tasks such as query analysis, knowledge base construction, recommendation, and search. However, we argue that most prior studies extract formal and overly general concepts from Wikipedia or static web pages, which are not representing the user perspective. In this paper, we describe our experience of implementing and deploying ConcepT in Tencent QQ Browser. It discovers user-centered concepts at the right granularity conforming to user interests, by mining a large amount of user queries and interactive search click logs. The extracted concepts have the proper granularity, are consistent with user language styles and are dynamically updated. We further present our techniques to tag documents with user-centered concepts and to construct a topic-concept-instance taxonomy, which has helped to improve search as well as news feeds recommendation in Tencent QQ Browser. We performed extensive offline evaluation to demonstrate that our approach could extract concepts of higher quality compared to several other existing methods. Our system has been deployed in Tencent QQ Browser. Results from online A/B testing involving a large number of real users suggest that the Impression Efficiency of feeds users increased by 6.01% after incorporating the user-centered concepts into the recommendation framework of Tencent QQ Browser.Comment: Accepted by KDD 201

Physicochemical Properties and Lipophilicity of Polydatin-Lecithin Complex

Purpose: To investigate the physicochemical properties and lipophilicity of polydatin-lecithin complex.Methods: The complex of polydatin-lecithin was prepared by solvent method. The physicochemical properties of the complex were investigated by ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), differential scanning calorimetry (DSC), x ray diffractometry (XRD) and scanning electron microscopy (SEM). Its solubility in n-octanol at 25 °C was examined by high performance liquid chromatography (HPLC).Results: The UV and IR spectra of the complex showed an additive effect of polydatin-lecithin, in which the characteristic absorption of their respective peaks were retained. DSC and XRD results suggest that the complex mainly showed the presence of lecithin with the characteristic peaks for polydatin absent, while SEM demonstrated that polydatin was dispersed in lecithin. HPLC analysis found that the solubility of polydatin in n-octanol at 25 °C was enhanced from 0.41 mg/mL to 21.98 mg/mL by complexing with lecithin, indicating that the lipophilicity of polydatin was significantly improved.Conclusion: Polydatin and lecithin in the complex are combined by non-covalent bonds, and did not form a new compound. The lipophilicity of polydatin increased to 21.98 mg/mL from 0.41 mg/mL as a result of complexation.Keywords: Polydatin, Lecithin, Complex, Physicochemical property, Lipophilicit