Real-time train rescheduling plays a vital role in railway transportation as it is crucial for maintaining punctuality and reliability in rail operations. In this paper, we propose a rescheduling model that incorporates constraints and objectives generated through human-computer interaction. This approach ensures that the model is aligned with practical requirements and daily operational tasks while facilitating iterative train rescheduling. The dispatcher's empirical knowledge is integrated into the train rescheduling process using a human-computer interaction framework. We introduce six interfaces to dynamically construct constraints and objectives that capture human intentions. By summarizing rescheduling rules, we devise a rule-based conflict detection-resolution heuristic algorithm to effectively solve the formulated model. A series of numerical experiments are presented, demonstrating strong performance across the entire system. Furthermore, the flexibility of rescheduling is enhanced through secondary analysis-driven solutions derived from the outcomes of human-computer interactions in the previous step. This proposed interaction method complements existing literature on rescheduling methods involving human-computer interactions. It serves as a tool to aid dispatchers in identifying more feasible solutions in accordance with their empirical rescheduling strategies.

Based on Network Agenda Setting Model, this study collected 42,516 media reports from Party Media, commercial media, and We Media of China during the COVID-19 pandemic. We trained LDA models for topic clustering through unsupervised machine learning. Questionnaires (N = 470) and social network analysis methods were then applied to examine the correlation between media network agendas and public network agendas in terms of explicit and implicit topics. The study found that the media reports could be classified into 14 topics by the LDA topic modeling, and the three types of media presented homogeneity in the topics of their reports, yet had their own characteristics; there was a significant correlation between the media network agenda and the public network agenda, and the We Media reports had the most prominent effect on the public network agenda; the correlation between the media agenda and the implicit public agenda was higher than that of the explicit public agenda. Overall, findings showed a significant correlation between network agendas among different media.

Based on event history analysis, this study examined the survival distribution of the duration of online public opinions related to major health emergencies and its influencing factors. We analyzed the data of such emergencies (N = 125) that took place in China during a period of 10 years (2012-2021). The results of the Kaplan-Meier method and Cox proportional hazards regression analysis showed that the average duration of online public opinions regarding health emergencies is 43 days, and the median is 19 days, which dispels the myth of the "Seven-day Law of Propagation." Furthermore, the duration of online public opinions can be divided into three stages: the rapid decline stage (0-50 days), the slowdown stage (51-200 days), and the disappearing stage (after 200 days). In addition, the type of event, and the volume of both social media discussion and traditional media coverage all had significant impacts on the duration. Our findings provide practical implications for the carrying out of targeted and stage-based governance of public opinions.

In this paper the propagation characteristics of large-scale multi-antenna communication system are investigated. we give an insight into sub-channel correlation, and from which the non-stationary characteristics are deduced. Some in-field channel sounding are carried out with interesting frequencies of 1.4725GHz and 4.5GHz. Regarding to the channel measurements and data analysis we take an educated guess, and construct a birth-and-death-based Markov Model to characterize the multipath cluster’s evolution over the array, which explained the micro-changes of the radiation propagation environment. And the model is found to be highly coincide with propagation theory.

[研究目的]中国已成为海外跨国公司人工智能专利布局的重要目标市场,探究海外跨国公司在华人工智能专利布局及竞争态势,有助于防止其在华进行垄断式专利布局,为中国企业和政府机构在长期性科技竞争中制定和调整专利战略提供理论依据.[研究方法]从IPC专利分类视角出发,利用马尔可夫链和显性技术比较优势指数,识别海外跨国公司在华人工智能专利布局的演进特征和演变结果,运用结构相似度和结构调整度指数,衡量中国市场人工智能专利竞争态势.[研究结论]海外跨国公司采取了积极扩张的专利策略,不断扩大人工智能专利布局范围;布局重心由基础算法向基础硬件和垂直应用领域转移,形成了25个新兴领域和17个重点领域,部分领域持续发展成为较稳定的优势领域;中国同美国、日本、韩国和欧洲的人工智能跨国公司技术互补性降低、竞争程度增加,特别是与美国跨国公司的技术竞争最为激烈.

私域空间,是相对于"公域空间"而言的概念,涵盖了非公共性的家庭生活以及公域中的个人参与.近年来在"私域流量"传播模式主导下,网民的信息接收和传播行为在很大程度上受其所嵌入的私域空间影响.相应的,网络舆论生态发生了极大的变化,对其效果研究方法、网络空间治理模式均急需新的探索.

Given a vehicle image,vehicle re-identification aims to find the same vehicle caught by other cameras,it can be regarded as a sub-problem of image retrieval.In the real traffic surveillance system,vehicle re-identification can play a role in locating,supervising and criminal investigation of target vehicles.With the rise of deep neural networks and the release of large-scale dataset,improving the accuracy and efficiency of vehicle re-identification has become a research focus in the field of computer vision and multimedia in recent years.The vehicle re-identification methods from different perspectives were classified,and the overview,comparison and analysis in terms of feature extraction,design and performance were given in detail,and the challenges and future trends of vehicle re-identification were predicted.

In this paper a novelty Massive Multiple Input Multiple Output (MIMO) channel model based on the birth-and-death process of multipath clusters is proposed. First, Massive MIMO measurements are conducted in typical outdoSor scenarios with the bandwidth of 100 MHz at frequencies of 1.4725 and 6 GHz, respectively, following with the investigation of radio propagation characteristics over antenna array. Then we research on the subchannel correlation and nonstationary based on the channel sounding experiments. Furthermore, we build up a Markov chain to characterize the birth-and-death process of the multipath clusters over the array, which is helpful to bring deeply insight into the cluster evolution over the antenna array axis. And the analysis results are consistent with the theory of the cluster's visible region. At last, the paper systematically demonstrates how does the spatial correlation influence the capacity of the communication system. The whole research work aims to contribute the radio channel modeling of the fifth-generation (5G) Massive MIMO communication system.

网络新闻聚合平台的版权侵权行为已引起学界与业界的普遍担忧.本文从网络聚合新闻的版权保护困境出发,分析其聚合逻辑、挖掘其运作机制,发现网络新闻聚合平台的新闻数据抓取方式存在一定的版权侵权问题,其分发机制不可避免地带来利益分配纠纷,给新闻原创作者造成重大利益损失,现有的版权保护方法也难以适应网络聚合新闻的创作环境.因此,本文提出区块链技术是目前防止网络新闻聚合平台侵权行为最有效的手段,并对其技术接人的可行性和方法论进行探讨,提出基于时间戳记录保护的技术方法、基于区块链ID的组织方法、基于智能合约的长效方法,以期对新闻版权保护这一难题的解决有所助益.

Recent studies reveal that beliefs about others' beliefs, or “second-order” beliefs, play a larger role in environmental public opinion than previously recognized. However, questions remain regarding which second-order beliefs should be most predictive, and under what conditions. We explored these questions within the context of China's coal-to-gas policy—a recent national energy conversion that has created economic challenges for millions of Chinese households that rely on inexpensive coal for heating—by conducting 602 face-to-face interviews with a socioeconomically diverse sample of residents from eight provinces and two large municipalities. Interviews occurred in the winter of 2018, during the policy's rollout period. Although they may be expected to have limited predictive power under these conditions, results showed that second-order beliefs, particularly those regarding proximal reference groups (e.g., “My friends and family” and “Chinese people in general”), strongly predicted individual-level policy support, over-and-above key demographic variables and first-order environmental beliefs.

The spectral efficiency and energy efficiency of the uplink of massive MIMO-OFDM system is studied using mixed-precision Analog-Digital Converter (ADC) and Zero-Forcing (ZF) reception algorithm at the receiver. By using the additive quantization noise model to analyze the performance of the system, the approximate closed expression of the spectral efficiency and energy efficiency of the whole system is derived, and the correctness of the expression is proved by simulation. The research results show that the spectral efficiency of the system is related to the transmission power of each user, the number of antennas at the receiver and the quantization accuracy of the receiver. Numerical and simulation results also show that the performance loss caused by the low-precision ADC can be compensated by increasing the number of antennas at the base station.

In this paper, we investigate the performance of millimeter-wave massive MIMO (Multiple-input multiple-output) system with low-precision Analog to Digital Converters (ADCs). The nonlinear quantization process is transformed into linear through Additive Quantization Noise Model (AQNM), and the closed-form expression of the uplink achievable rate is derived. The expression correctly describes the effect of the transmission power of the user, number of Radio Frequency (RF) chains at the base station, number of propagation paths and ADC quantization bits on the achievable rate. Moreover, the simulation analysis proves the correctness of the closed-form expression and obtains the conclusion that the peak of energy efficiency will be achieved when the 3 bit ADC is configured at the receiver.

In this paper, we propose a novel channel estimation technique for frequency-division duplex (FDD)-based massive multiple-input multiple-output (MIMO) systems. Cascaded precoding has been adopted in FDD massive MIMO systems in order to reduce the dimension of physical channels so that the traditional channel estimation can be employed over a low-dimensional effective channel. However, due to the lack of a priori knowledge of the downlink channels, traditional channel estimation approaches can hardly achieve the minimum mean-square-error (MMSE) performance. To this end, we propose a limited feedforward strategy for downlink channel estimation based on the parametric model. In the parametric model, the channel frequency responses are represented by the path delays and the corresponding complex amplitudes. The path delays of uplink channels are first estimated and quantized at the base station, then fed forward to the user equipment (UE) through a dedicated feedforward link. In this way, the UE can obtain the a priori knowledge of the downlink channel under the assumption of the reciprocity between downlink and uplink path delays. Our analysis and simulation results show that the limited feedforward method can achieve near-MMSE performance.

基于智能算法的“千人千面”个性推荐技术重塑了新闻生产及传播的各个环节,政策类新闻特点决定了其首当其冲受到影响.本文探讨了新技术对政策类新闻在内容结构、受众分化、推送渠道及动态评价方面产生的影0向,同时针对四类挑战提出相应优化策略.

This paper investigates the cross-correlation characteristics of large-scale parameters (LSPs) and small-scale fading (SSF) for high-speed railway (HSR) multilink propagation scenarios, based on realistic measurements conducted on Beijing to Tianjin HSR line in China. A long-term evolution-based channel sounding system is utilized in the measurements to obtain the channel data. By applying a proposed time-delay based dynamic partition method, multi-link channel impulse responses are extracted from the raw channel data. Then, the statistical results of LSPs, including shadow fading, K-factor, and root-mean-square delay spread are derived and the cross-correlation coefficients of these LPSs are calculated. Moreover, the SSF spatial correlation and cross-correlation of SSF are analyzed. These results can be used to exploit multi-link channel model and to optimize the next-generation HSR communication system.

The closure of the North Tianshan Ocean between the Junggar Terrane and the Yili Block is a longtime debated issue in literature, because of the different understanding of the Carboniferous volcanic rocks in the northern margin of the Yili Block. This study presents new geochronological and whole-rock geochemical data for the granitic rocks from the Borohoro pluton to provide constraints on the tectonic regime for the northern West Tianshan during the Carboniferous. LA-ICP-MS U-Pb dating results reveal two magmatic phases for the Borohoro pluton. The former magmatic activity in the Early Carboniferous formed the fine-grained granodiorite (332 Ma). The later magmatic activity occurred during the Late Carboniferous (305-300 Ma), forming a diversity of granitic rocks, involving quartz diorite, granodiorite and granite. Geochemical and mineralogical studies reveal that the studied granitic rocks from the Borohoro pluton all belong to metaluminous to weakly peraluminous, calc-alkaline I-type granites. They are characterized by enrichment in LILEs relative to HFSEs, and depletion of Nb, Ti and P, typical of continental arc-type granites. The intermediate SiO2, high Al2O3, and relatively low Fe2O3T, Mg and TiO2 contents reflect that these granitic rocks are mainly crust-derived. But the high Mg-# values for most samples and the occurrence of microgranular mafic enclaves indicate that their magma sources were mixed by mantle-derived components. Especially, the Late Carboniferous rocks define an elegant mixing trend in both the Rb-Rb/V and the 1/V-Rb/V diagrams, consistent with mixing between magmas from subcontinental lithospheric mantle and mafic lower crust. Taking into consideration of the facts that all the Devonian to Carboniferous granitoids belong to calc-alkaline I-type granites, and granitoids of A-type didn't appear until the Early Permian, we suggest that the subduction of the North Tianshan Ocean continued to the Late Carboniferous, generating the granitic rocks of the Borohoro pluton.

Massive multiple‐input–multiple‐output (MIMO) is acknowledged as a key technology for the fifth generation of wireless communication systems, theoretically proved to be of higher throughput, better robustness, superior spectrum‐ and energy‐efficiency with a general presumption that the channels tend to pairwise orthogonal with the increasing of the asymmetrical antenna pairs. Recently, more and more researches have cast light on massive MIMO system modelling. However, few investigations have been done on spatial characteristics of massive MIMO systems, especially the systems equipped with more than 100 antennas. This study focuses on the massive MIMO channel spatial characteristics based on indoor line‐of‐sight radio propagation measurement at 1.4725 GHz, and extracts spatial parameters such as angle of arrival, angle of departure and power azimuth spectrum from experimental data. The angles of departure (AODs) show a linear decrease along the linear antenna array, which are in agreement with the simulation of the ray tracing. On the basis of the realistic results of angular spread and the Gaussian density model, the investigation proves that antenna elements are deeply correlated and the envelope correlation coefficients show negative exponential down‐trend with the increasing of antenna spacing in massive MIMO systems.

This paper presents a traffic speed estimation method based on longest common subsequence. The study focuses on user location update mechanism of mobile phone network to reconstruct mobile phone trajectory. The main contribution of this paper is development of a systematic framework for estimating vehicle trajectories from mobile phone location data by longest common subsequence matching algorithm. This framework consists of five steps: vehicle trajectories reconstruction, object road handover sequence generation, vehicle trajectories matching, similarity measurement and traffic speed estimation. First, we analyzed the location update theory to reconstruct vehicle trajectories and generate object road handover sequences. Then, we proposed a vehicle trajectories matching method under the inspiration of longest common subsequence and designed a similarity measurement algorithm that satisfies the specific condition. Moreover, traffic speed can be estimated. At last, in the experiment part, we compared the results between estimated speed in this paper and detected speed by microwave detectors. The estimated speed is consistent with detected speed and has a good precision.

与传统的多输入多输出系统(MIMO)相比,由于大规模MIMO系统基站端配备了大量天线,其能量效率和频谱效率都有了显著的提高.然而大规模MIMO也意味着基站端需要安装大量的射频(RF)链路,从而大大提高了系统成本和系统功耗,因此天线选择技术可以成为降低大规模MIMO系统成本和功耗的潜在解决方案之一.本文研究了大规模MIMO系统中发射天线选择技术,通过结合和改进现有的两种天线选择基准的算法,在综合考虑大规模MIMO系统性能和复杂度的前提下提出了一种新型发射天线选择算法.通过分析仿真结果:可以得知提出的新型发射天线选择通过牺牲少量的复杂度,提升了多用户大规模MIMO系统的频谱效率,并可以看出,本文所提的天线选择算法更适用于低SNR的情况,更适合实际的通信系统.