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大规模多输入多输出（MIMO）技术是5G的关键技术之一,由导频资源有限引起的导频污染是制约其发展的主要瓶颈之一,为此必须对宝贵的导频资源进行合理地分配以减小导频污染。已有的导频分配方案大多考虑静态导频分配,无法很好地适应用户位置不断变化的移动通信环境。文章针对大规模MIMO系统中用户移动时的导频分配问题,提出了一种动态迁移导频分配方法。该方法在两个相邻时隙间仅针对移动幅度较大的用户进行额外的导频优化,根据分配方案选择一个用户与之进行导频交换,对于其他的用户不改变原分配导频。复杂度分析及仿真结果表明,该算法相较于传统的导频分配方法可以显著地降低计算复杂度,并且与传统的导频分配方法具有相近的频谱效率,具有较高的实用价值。

电力光网络的关键链路对业务质量的安全和可靠保障具有重要作用。关键链路识别方法的研究有助于提高识别过程的高效性和准确性。文章首先将最短路径敏感度作为网络效能测度,并通过计算网络节点间最短路径长度,研究链路状态恶化对网络效能的影响;然后,基于跳数最少、时延最短和可靠性最高等3种不同目标,对链路状态变化与最短路径敏感度关联关系进行统计分析,得到关键链路指标;最后,以实际的省级电力通信网为算例,验证方法的可行性和正确性。研究结论对电力光网络的规划设计和运行维护具有参考价值。

在SM（空间调制）系统中,基于差分编码思想对4根发射天线情况提出了一种新的DSM（差分空间调制）方案。在接收端解调时采用差分直接检测法,即根据前后相邻两时刻的接收信号差进行解调。该方法只需测定初始的信道参数,后续接收端与发送端均不需要知道信道状态信息,通信过程中可以抵抗信道参数变化。对DSM方案进行了性能仿真,结果表明,该四进制DSM方案能够实现通信,并且具有较好的抗信道参数变化性能。

Agricultural film residues which limit crop growth and cause soil pollution become increasingly serious. Exploring the effects of agricultural film residues with different amounts on the growth of maize and soil environment can provide theoretical support for the scientific and rational use of agricultural film. In this study, the distribution of residual film in maize farmland with film mulching in Hetao irrigation region of Inner Mongolia was taken as the research object, and 6 residual film gradients were set, including 0 (CK), 75kg·ha−1, 150kg·ha−1, 300kg·ha−1, 450kg·ha−1 and 600kg·ha−1, and the effects of different amounts of the agricultural film residues on maize yield and its components, root weight and taproot number, soil moisture content and bulk density were analyzed. The results showed that: (1) there was a negative correlation between the amount of film residues and the yield of maize, and there was a significant difference in the yield when the amount of film residues exceeded 300kg·ha−1 (P<0.05). With the increase of film residues, the bald tip of maize increased, and the 100-grain weight decreased significantly (P<0.05). (2) The increase of the film residues reduced the root quality and taproot numbers of maize, which were not conductive to the growth and development of the root system, and the ability of the root system to absorb water and nutrients from the soil decreased. (3) The film residues hindered the transport of soil water, soil water seeped slowly when the amount of film residues reached 300−450kg·ha−1, and the film residues over 600kg·ha−1 hindered the migration of soil capillary water and the infiltration of precipitation. Therefore, the use of scientific and reasonable ways to control soil residual film pollution control and recycle plastic film to reduce plastic film residues in the soil is helpful to promote the improvement of maize yield and soil quality, and realize the green and sustainable development of agriculture. [ABSTRACT FROM AUTHOR]

Copyright of Guihaia is the property of Guihaia Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ordnance Equipment Engineering is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal of Nanjing Medical University: Natural Sciences is the property of Journal of Nanjing Medicial University (NMU) Medical Publications Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The research of music emotion recognition has broad application prospects in the fields of music intelligent recommendation and music visualization. Aiming at the problem that only using low‑level audio features for emotion recognition has limited effectiveness and poor interpretability. Firstly, an emotion recognition model ERMSLM based on MIDI (musical instrument digital interface) data is constructed, which can learn the semantic information of notes. The features of this model are composed of melodic features extracted with skip‑gram and LSTM (long short‑term memory), tonal features extracted by pre‑trained MLP and manually constructed features. Secondly, an emotion recognition model ERMBT based on text data that integrates lyrics and social tags is constructed. The lyrics features are composed of emotional features extracted with BERT, emotional dictionary features constructed by using ANEW lists and TF-IDF features of lyrics. Finally, two multimodal fusion models of feature‑level fusion and decision‑level fusion are constructed based on MIDI and text data. The experimental results show that the ERMSLM and ERMBT models can achieve accuracies of 56. 93% and 72. 62% respectively. And the decision‑level multimodal fusion model is more effective. [ABSTRACT FROM AUTHOR]

Trailers need to operate under various conditions, including full load bending, full load twisting, emergency braking, and sharp turns. In order to solve the problem of poor reliability and safety of the on-board system of the trailer under full load condition, a three-dimensional assembly model of a small logging trailer was established, and static analysis was performed. Through finite element analysis, we studied the structural deformations and stress distributions of the trailer under four typical working conditions. Under full load bending conditions, the maximum displacement was 4. 517 7 mm, the maximum stress was 115. 19 MPa, and the safety factor was 3. 08. Under full load twisting conditions, the maximum displacement was 0. 984 48 mm, the maximum stress was 71. 929 MPa, and the safety factor was 4. 935. Under full load braking conditions, the maximum displacement was 4. 994 6 mm, the maximum stress was 120. 05 MPa, and the safety factor was 2. 957. Under emergency turning conditions, the maximum displacement was 4. 365 8 mm, the maximum stress was 104. 64 MPa, and the safety factor was 3. 39. Results showed that the small skidding trailer designed in this study had strong stability under full load working conditions in the forest, which ensured the reliable collection and transportation of wood. Future research can further optimize trailer design and performance to meet evolving needs and environmental requirements. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forest & Environment is the property of Journal of Forest & Environment Editorial and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Drilling Fluid & Completion Fluid is the property of Drilling Fluid & Completion Fluid Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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In order to solve the complex derrick steel structure damage identification problem, an innovative combination of timedomain multi-parameter information fusion and machine learning was proposed. Based on the acceleration response signal of the derrick steel structure, a derrick steel structure damage identification method based on principal component analysis and support vector machine was proposed. Firstly, the acceleration response signal of the derrick steel structure under the impact load was extracted by the acceleration sensor, and then several time-domain features were obtained including impulse factor, margin factor and cliffness. Secondly, the above features were fused according to the principal component analysis to form a new comprehensive feature while ensuring that as much information as possible was retained. Finally, the feature data was input into the support vector machine model for damage identification. The above theories were used for simulation and identification, and a laboratory model of the ZJ70 derrick steel structure was tested and analyzed to verify the feasibility and generality of the method. The results show that the accuracy of single or multiple damage identification of derrick steel structure by the method is high, and it is simple and easy to implement with less time consuming. [ABSTRACT FROM AUTHOR]

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Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to analyze the impact of data uncertainty on the results of fish-index of biological integrity(F-IBI), a F-IBI was constructed based on the historical information and ecosystem characteristics of the surrounding waters of Chongming Island, China. A total of 12 indices related to fish species composition, trophic structure, tolerance, reproductive character, heath conditions and biomass were included in this F-IBI. Fish community information in waters near Chongming Island were collected from surveys in August and November 2020. The F-IBI was used to evaluate the state of ecosystem health of study area. Besides, the effects of survey data uncertainty on the projection of F-IBI for the surrounding waters of Chongming Island were evaluated by computer simulation. Five indices (total number of fish species, percentage of number of pollution sensitive fishes, percentage of number of piscivorous species, percentage of number of adhesive egg fishes and catch per haul per hour) from 12 indices were selected as simulation indices. The effect of single index uncertainty, multiple indices uncertainty and different levels of uncertainty on the final estimation result of F-IBI were evaluated. Results indicated that the F-IBI was in the "poor" grade of the surrounding waters of Chongming Island in August and November 2020. Uncertainty analysis showed that a set of 30% at the coefficient of variance of indices did not affect the evaluation grade of F-IBI, but the score changed to a certain extent.With the increase of index uncertainty, the fluctuation range of the evaluation results of F-IBI increased gradually. The influence strength of each index was related with the position of survey data in the range in the scoring section of F-IBI system. The results of this study emphasize the importance of considering the natural fluctuation range of the evaluation index in the evaluation of F-IBI in waters near Chongming Island. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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