A Novel Orthogonal LoRa Multiple Access Algorithm for Satellite Internet of Things

In recent years,LoRa has been extensively researched in the satellite Internet of Things(IoT).However,the multiple access technology of LoRa is still one of the bottlenecks of satellite IoT.To improve the multiple access performance of LoRa satellite IoT,based on the orthogonality of LoRa symbols in the fractional domain,this paper proposes a low complexity Orthogonal LoRa Multiple Access(OLMA)algorithm for multiple LoRa users occupying the same frequency bandwidth.The algorithm introduces the address code to divide the fractional bandwidth into multiple parts,and the OLMA users with different address codes occupy different parts to transmit the information code,thus avoiding mutual interference caused by collisions in the same frequency bandwidth.The multiple access capability of OLMA can be flexibly configured only by simply adjusting the length of the address code according to the actual application requirements of data transmission.Theoretical analysis and simulation results show that the OLMA algorithm can greatly improve the multiple access capability and the total transmission bit rate of LoRa IoT without changing the existing LoRa modulation parameters and process.

Establishment of an arsenic-resistant human gallbladder carcinoma cell line and analysis of the differential expressions of genes associated with apoptosis

Objective： The aim of the study was to establish an arsenic trioxide （ATO）-resistant cell line of human gallbladder carcinoma, GBC-SD/ATO, and to analyze the differential expressions of its apoptosis-associated genes, so as to investigate a correlation between ATO induced resistance of gallbladder carcinoma and expressions of apoptosis associated genes. Methods： The resistant cell line was obtained in vitro by culture of human gallbladder carcinoma cell line GBC-SD with increasingly stepwise concentrations of ATO. The sensitivities of GBC-SD cells and GBC-SD/ATO cells to ATO were determined by MTT assay respectively, cDNA microarray containing 458 apoptosis-related human genes was used to compare the gene expression profiles of GBC-SD/ATO cells and corresponding sensitive cell line GBC-SD. Results： GBC-SD/ATO cell line was established successfully after 8 months of exposure to increasing concentrations of ATO. Compared with the parental cell line, GBC-SD/ATO was 13.6 times more resistant to ATO. Of the 458 apoptosis-related genes, 17 genes were detected having 〉 2-fold difference of expression between the GBC-SD/ATO and GBC-SD cells, with 6 genes up-regulated and 11 genes down-regulated in GBC-SD/ATO cells. Conclusion： The 17 genes invoJved in the apoptosis pathway might be relevant to the resistance of GBC-SD/ATO cells to ATO, suggesting that the modulation of expression of apoptosis-related genes may be a main mechanism of acquired resistance in GBC-SD/ATO.

Reversal of CQ11, a chloroquine derivative, on multidrug resistance in doxorubicin-resistant breast cancer cell line MCF/DOX

Objective： To investigate the reversal effect of CQ11, a chloroquine derivative, on multidrug resistance （MDR） in doxorubicin （DOX）-resistant human breast carcinoma cell line MCF/DOX. Methods： Cells of a human breast cancer cell line, MCF, and its DOX-resistant variant, MCF/DOX, were cultivated with DOX and/or CQ11. The cytotoxicity of drugs in vitro was assayed by MTT method. The accumulation of DOX in these cells was detected by fluorescence spectrophotometer. Results： MCF/DOX cells were 119 times more resistant to DOX in comparison with M CF cells. After simultaneous treatment with CQ 11 at the concentrations of 1.0, 2.5 and 5.0 μmol/L, the IC50 of DOX for MCF/DOX cells decreased from 3.1 ±0.47 μmot/L to 0.58 ± 0.032, 0.19 ± 0.012 and 0.081 ± 0.015 μmol/L, respectively, thus, increasing the DOX sensitivity by 5.3-fold （P 〈 0.01）, 16- fold （P 〈 0.01） and 38-fold （P 〈 0.01）, respectively. In the accumulation assay of DOX, simultaneous incubation of MCF/DOX cells with CQ11 significantly increased the DOX accumulation in MCF/DOX cells. No such results were found in parental MCF cells. Conclusion： CQ11 had strong MDR reversal effect by enhancing intracellular DOX accumulation in MCF/DOX cells, indicating that CQ11 may be a promising MDR chemosensitivity.

A Personalized Cloud Services Recommendation Based on Cooperative Relationship between Services

A personalized recommendation for cloud services, which is based on usage history and the cooperative relationship of cloud services, is presented. According to service groups, a service group could be defined as several services that were used together by one user at a time, and cooperative relationship between each two services can be calculated. In the process of recommendation, the services which are highly related to the service that the user has selected would be obtained firstly, the result should then take the QoS (Quality of Service) similarity between service’s QoS and user’s preference into account, so the final result combining the cooperative relationship and similarity will meet the functional needs of users and also meet the user’s personalized non-functional requirements. The simulation proves that the algorithm works effectively.

Resource allocation algorithm for multi-user MIMO-OFDM downlink with correlated channels

To minimize transmitting power,an adaptive resource allocation algorithm is proposed for multi-user multiple input multiple output-orthogonal frequency division multiplexing(MIMO-OFDM)downlink with correlated channels,which,based on the user’s grouping according to their spatial correlations,combines the shared manner and the exclusive manner to allocate sub-carriers.Between different groups the shared manner with a null steering method based on group marginal users is applied,whereas within a group the exclusive manner is applied.The simulations show that the power efficiency and spectral efficiency are improved;the base station transmitting antenna number and the computational complexity is decreased.

Adding power of artificial intelligence to situational awareness of large interconnections dominated by inverter‐based resources

Large‐scale power systems exhibit more complex dynamics due to the increasing inte-gration of inverter‐based resources(IBRs).Therefore,there is an urgent need to enhance the situational awareness capability for better monitoring and control of power grids dominated by IBRs.As a pioneering Wide‐Area Measurement System,FNET/GridEye has developed and implemented various advanced applications based on the collected synchrophasor measurements to enhance the situational awareness capability of large‐scale power grids.This study provides an overview of the latest progress of FNET/GridEye.The sensors,communication,and data servers are upgraded to handle ultra‐high density synchrophasor and point‐on‐wave data to monitor system dynamics with more details.More importantly,several artificial intelligence(AI)‐based advanced appli-cations are introduced,including AI‐based inertia estimation,AI‐based disturbance size and location estimation,AI‐based system stability assessment,and AI‐based data authentication.