Self-adaptive nonoverlapping sequential pattern mining

Applied Intelligence - Repetitive sequential pattern mining (SPM) with gap constraints is a data analysis task that consists of identifying patterns (subsequences) appearing many times in a...     

Overburden fracture evolution laws and water-controlling technologies in mining very thick coal seam under water-rich roof

Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine, the universal discrete element (UDEC) software was used to simulate the overburden fracture evolution laws when mining 4# coal seam. Besides, this study researched on the influence of face advancing length, speed and mining height on the height of the water flowing fractured zones (HWFFZ), and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow. Based on those mentioned above, this research proposed the following water-controlling technologies: draining the roof water before mining, draining goaf water, reasonable advancing speed and mining thickness. These water-controlling technologies were successfully used in the field, thus ensured safely mining the very thick coal seam under water-rich roof.     

LLDPE吹塑薄膜加工助剂的研究与应用

本文介绍了LLDPE的加工特性,考察了助剂对LLDPE加工性的影响及加工助剂的协同效果,使用多组分助剂母料在LDPE吹膜机上可高效低耗生产LLDPE农用薄膜。     

基于ME-MEEMD的构件残余应力检测研究

针对焊接钢板内部的残余应力,由于采集振动信号的非线性和非平稳性,采用希尔伯特-黄变换(HHT)对振动信号分析处理。在对得到的信号进行分析时,选择镜像延拓(ME)以及改进的集总平均经验模态分解(MEEMD)相结合的方式,目的是防止在经验模态分解时产生模态混叠以及端点效应等对最终的实验结果产生影响。求解出各阶固有模态函数的模态能量,与正常信号分析对比,从能量角度实现对构件残余应力的检测,得出信号能量与残余应力之间的关系。     

AS／MBS／EVA三元共混体系力学性能及微观形态

研究了AS/MBS/EVA三元共混体系的力学性能及微观形态。采用EVA作为相容剂改善核壳型粒子MBS在AS基体中的分散 ,达到良好效果 ,在保持AS良好弯曲性能的同时 ,提高了基体的缺口冲击强度。     

综合地球物理信息的孔隙率预测方法及应用效果分析

在油藏综合研究中,储层孔隙率参数的准确求取是一项关键性技术,本文在分析总结已有的储层参数预测方法的基础上,综合利用地质,地球物理信息,通过数学统计等方法,采用逐步线性回归,相关滤波,神经网络,协克里金,非参数回归等预测孔隙参数平面分布,通过实例分析比较了各种方法的地质效果,归纳总结出上述方法的特点及其应用条件。     

A Jointed Resource Allocation and Multiuser Pairing Algorithm with Low Complexity for SC-FDMA Systems

Considering practical constraints in the single-carrier frequency division multiple access system, this paper proposes a jointed resource allocation and multiuser pairing algorithm with low complexity. It initially schedules the first user and carries out resource allocation and then selects the second and following pairing users in turn. Meanwhile, the proportional fair criterion is considered independently in the scheduling process for every pairing user. The simulation results show that, excluding its considerably lower complexity, the proposed algorithm has better throughput and fairness than the existing algorithms.     

Optimal Location of the Secondary Base Station for Broadcasting Cognitive Radio Networks with Spectrum Underlay

This paper focuses on where to place the secondary base station (SBS) so as to obtain the maximum coverage area for a broadcasting cognitive radio network with spectrum underlay. Aiming to solve this problem, the coverage area is first obtained, considering the interference constraints for the primary user (PU) and quality of service constraints for the secondary user. It is found that the location of the SBS takes an important role in the coverage area determination. Then, an optimal location of the SBS is derived to maximize the coverage area in the broadcasting cognitive radio network. Further, considering the local environment can largely determine the characteristics of radio propagation in practice, a typical scenario with an obstacle located between the PU and SBS is analyzed. Numerical results show that the optimal location of the SBS is different with different locations of the obstacle, and will converge to a fixed point as the distance between the PU and the obstacle increases when the obstacle is assumed to be a hill, which is exactly the optimal location of the SBS without the obstacle.     

一种CDMA接收机在单频点阻塞干扰环境中的性能分析

本文考虑同步码分多址通信系统在单频点阻塞干扰环境中,一种抗多址干扰单用户检测接收机(I.Acax等人1994年提出)的误码率特性.结果表明,这种接收机(A-T接收机)在系统用户数很大时仍具有良好的抗单频点阻塞干扰性能。     

时间异步全双工数字域分段卷积自干扰抑制技术

同时同频全双工(CCFD)多载波信号时间异步场景下,有用信号(SoI)与自干扰信号(SI)多径最大时差超出循环前缀长度(CP),有用信号与自干扰信号子载波不正交,造成频域自干扰抑制性能严重下降。针对上述问题,该文提出一种时间异步数字域分段卷积的自干扰抑制方法,建立了自干扰分段、频域重建、叠加抵消的自干扰抑制过程,提升了时间异步场景下自干扰抑制性能。理论和仿真结果表明,在异步场景下,采用分段卷积的自干扰抑制方法可以直接在频域重建自干扰,达到与同步场景相当的干扰抑制性能。