G3i地震采集系统多线束管理功能的应用

G3i地震系统随着地震勘探技术的进步,增加了多种新功能。G3i地震系统软件版本自5.014升级至5.016版本后,主机在管理排列方面增加了多线束采集管理模式。本文介绍了在多线束采集施工时,仪器如何对各个线束进行独立管理。

428XL仪器的Multiswath功能及其在浅海过渡带的应用

为了提高浅海过渡带地震勘探的生产效率,实现多线束同时作业,应沙特Aramco石油公司的要求,428XL仪器开发了Multiswath功能。本文以428XL V4.0为例,结合沙特某区块的生产实践,简单介绍了此功能,并从硬件和软件方面分析了这一功能存在的不足以及需要完善的地方,提出了改进建议,以便将其推广应用到所有的浅海过渡带的生产中。

428XL仪器在复杂地表井炮与可控震源混合施工探讨

428XL仪器是法国Sercel公司推出的地震数据采集系统。本文针对复杂地表多种震源混合施工时,激发点设置操作较为复杂的难题,提出了分线束分震源类型施工的操作方法,并分析研究了SPS文件格式,提出了SPS文件点代码定义操作方法。经实际应用,该方法快捷有效,可快速实现多种类型震源混合生产。

CEE-Gr:A Global Router with Performance Optimization Under Multi-Constraints

A global routing algorithm with performance optimization under multi constraints is proposed,which studies RLC coupling noise,timing performance,and routability simultaneously at global routing level.The algorithm is implemented and the global router is called CEE Gr.The CEE Gr is tested on MCNC benchmarks and the experimental results are promising.

Design and Implementation of An Active Multibeam Antenna System with 64 RF Channels and 256 Antenna Elements for Massive MIMO Application in 5G Wireless Communications

This paper focuses on the design and implementation of an active multibeam antenna system for massive MIMO applications in 5G wireless communications.The highly integrated active multibeam antenna system is designed and implemented at 5.8 GHz with 64 RF Channels and 256 antenna elements.The 64-channel highly integrated active multibeam antenna system provides a verification platform for digital beamforming algorithm and massive MIMO channel estimation for next generation wireless communications.

Waveguide Prism Based on Porous Silicon

The fabrication of the oxidized porous silicon waveguide prism is reported by selectively electrochemical anodisation process. The direction changes of light beams in TE and TM polarization out of this waveguide prism were respectively measured,and the experimental results were analyzed.

Three-dimensional multi-constraint route planning of unmanned aerial vehicle low-altitude penetration based on coevolutionary multi-agent genetic algorithm

To address the issue of premature convergence and slow convergence rate in three-dimensional (3D) route planning of unmanned aerial vehicle (UAV) low-altitude penetration,a novel route planning method was proposed.First and foremost,a coevolutionary multi-agent genetic algorithm (CE-MAGA) was formed by introducing coevolutionary mechanism to multi-agent genetic algorithm (MAGA),an efficient global optimization algorithm.A dynamic route representation form was also adopted to improve the flight route accuracy.Moreover,an efficient constraint handling method was used to simplify the treatment of multi-constraint and reduce the time-cost of planning computation.Simulation and corresponding analysis show that the planning results of CE-MAGA have better performance on terrain following,terrain avoidance,threat avoidance (TF/TA2) and lower route costs than other existing algorithms.In addition,feasible flight routes can be acquired within 2 s,and the convergence rate of the whole evolutionary process is very fast.

Angle-Threshold Random Beamforming Scheme for Multi-Antenna System

Codebook-based multiple input multiple output(MIMO) beamforming can significantly improve the system spectral efficiency with limited feedback and gets widely adopted.However,this scheme has a drawback of heavy feedback load that the sum feedback rate can be a bottleneck for the communication system,especially when the number of users is large.In this paper,a new scheme using pseudo-random beamforming vectors and angle based threshold in the feedback process is proposed.In the proposed scheme,both the base-station and the users have no need to store a codebook.In each access procedure,the base-station generates a pseudo-random beamforming vector,and each user calculates the angle between the beamforming vectors and its channel state information(CSI) vector.If the angle is less than a predefined angle-threshold,the user feeds back its channel quality indicators(CQI),otherwise it keep silence.Compared with the codebook based scheme,the proposed scheme can largely reduce the sum feedback rate with negligible throughput loss.In particular,when the system has a constraint on the total sum feedback rate in uplink channel,the proposed scheme can increase the system throughput significantly.

QoS Guarantees of Multiuser Video Streaming over Wireless Links: Delay Constraint and Packet Priority Drop

To provide a certain level of Quality of Service (QoS) guarantees for multiuser wireless downlink video streaming transmissions, we propose a multiuser scheduling scheme for QoS guarantees. It is based on the classic Queue-Length-Based (QLB)-rate maximum scheduling algorithm and integrated with the delay constraint and the packet priority drop. We use the large deviation principle and the effective capacity theory to construct a new analysis model to find each user's queue length threshold (delay constraint) violation probability. This probability corresponds to the upper bound of the packet drop probability, which indicates a certain level of statistical QoS guarantees. Then, we utilize the priority information of video packets and introduce the packet priority drop to further improve the quality perceived by each user. The simulation results show that the average Peak Signal to Noise Ratio (PSNR) value of the priority drop is 0.8 higher than that of the non-priority drop and the PSNR value of the most badly damaged video frame in the priority drop is on an average 4 higher than that of the non-priority drop.

Planning for space station long-duration orbital mission under multi-constraints

An integrated nonlinear planning(NLP) model is built for space station long-duration orbital missions considering both the vehicle visiting schedules and the interaction effects between target phasing,vehicle return adjusting and Earth observation aiming.A two-level optimization approach is proposed to solve this complicated problem.The up-level problem employs the launch times of visiting vehicles as design variables,considers the constraints of crew rotations,resource resupplies and rendezvous launch windows,and is solved by a genetic algorithm.The low-level problems employ the maneuver impulses and burn times within each orbital mission as design variables,and a high-efficient shooting iteration method is proposed based on an analytical equation for the phase angle correction considering the J 2 perturbation.The results indicate that the integrated NLP model for space station long-duration orbital missions is effective,and the proposed optimization approach can obtain the optimal solutions that satisfy the multiple constraints and reduce the total propellant consumption.

A THEOREM ON PLURICANONICAL MAPS OF NONSINGULAR MINIMAL THREEFOLDS OF GENERAL TYPE

Let X be a complex nonsingular projective threefold of general type. It is shown that the dimension of the image of X through m-canonical maps is at least two for every m 3.