移动边缘计算卸载策略综述

随着科技的发展,智能移动设备的应用越发普及.然而,移动设备由于自身资源及计算能力的局限性,在处理计算密集型与时延敏感的应用时常面临着能力不足的情况.移动边缘计算(Mobile Edge Computing,MEC)中的计算卸载技术即将移动终端的计算任务卸载至移动网络的边缘,能有效地解决此类问题.同时相比于移动云计算中的计算卸载,MEC解决了高时延、网络负载与资源的占用等问题.本文围绕MEC计算卸载,首先介绍MEC的基础概念和基本架构及其应用场景;其次,从MEC计算卸载的体系结构、卸载决策和资源分配三个方面对现有研究工作进行总结对比;最后,从计算卸载决策算法、安全性、卸载节点发现和卸载数据依赖性四个方面展望移动边缘计算卸载未来的发展趋势和研究方向.

融合社会关系的社交网络情感分析综述

随着以用户为中心的Web 2.0的发展,社交网络平台以惊人的影响力渗入到生活的方方面面,对社交网络中的内容进行情感分析已经成为热点研究课题。Twitter、新浪微博等在线社交网站吸引了大量用户,通过用户间的交互,产生了许多包含用户间社会关系的信息,并且这些社会关系被广泛应用于社交网络的情感分析。融合社会关系的社交网络情感分析将用户间交互形成的社会关系应用到对用户发表在社交网络上内容的情感分析中,拟解决文本短小精炼、语义模糊、特征较为稀疏带来的情感分析准确率低的问题。对融合社会关系的社交网络情感分析研究进展进行综述,梳理、分析主要的方法,列举出其中的关键问题,最后阐述了研究趋势和展望,并进行了总结。

Residual energy based multi-relay selection and power allocation scheme in two-way relay network

In this paper, we have proposed a multi-relay selection and power allocation scheme for two-way relay network which aims to maximize the sum-rate of two-way relay system. First, to prolong network lifetime, a multi-relay selection strategy is proposed in which both channel state information （CSI） and remaining energy （RE） are considered. Next, a multi-relay power allocation algorithm based on convex optimization （MRPA-CO） is presented. To reduce the computational complexity, it can be divided into two steps： terminal nodes power allocation （TNPA） and relay nodes power allocation （RNPA）. Simulation results indicate that the proposed relay selection strategy can significantly prolong network lifetime compared to other relay selection strategies which consider CSI only, and the MRPA-CO algorithm has great advantage over equal power allocation （EPA） on sum-rate in two-way relay network.

Joint power allocation and subcarrier pairing in OFDM-based cooperative relaying system

This paper proposes rate-maximized （MR） joint subcarrier pairing （SP） and power allocation （PA） （MR-SP＆PA）, a novel scheme for maximizing the weighted sum rate of the orthogonal-frequency-division multiplexing （OFDM） relaying system with a decode-and-forward （DF） relay. MR-SP＆PA is based on the joint optimization of both SP and power allocation with total power constraint, and formulated as a mixed integer programming problem in the paper. The programming problem is then transformed to a convex optimization problem by using continuous relaxation, and solved in the Lagrangian dual domain. Simulation results show that MR-SP＆PA can maximize the weighted sum rate under total power constraint and outperform equal power allocation （EPA） and proportion power allocation （PCG）.

High isolation dual-element modified PIFA array for MIMO application

In this paper, we focus on antenna array design for mobile phone with finite volume and propose a novel antenna element structure by capacitive feeding and capacitive loading method based on the planar inverted F antenna （PIFA）. State-of-the-art development on this issue is reviewed. Then, a novel capacitively fed and capacitively loaded PIFA structure is proposed and studied. The results of the experiments showed that our structure can reduce the coupling of antenna elements from - 13.4 dB to -24.5 dB. Finally, a design with a bandwidth of 100 MHz centered at 2.35 GHz and envelopment correlation coefficient of 0.01 2 is provided and the diversity performance of the dual-element modified PIFA array is evaluated in both simulation and measurement. In a word, our novel design reaches broadband, miniaturization, high isolation and offers excellent diversity performance.

Analytical general results for handoff dwell time distribution in wireless networks

This article presents a general evaluation of handoff dwell time distribution based on geometric analysis methods. Considering the geometric characteristic of the deployed sector pattern, and the distribution of the users＇ position and the moving direction in the given sector, the general formulas of the probability density function of sector handoff dwell time are derived. Some numerical results are also presented for illustration.