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| 1 | Towards an Esox lucius inspired multimodal robotic fish显示文摘In this paper, we further explore multimodal locomotion via an updated robotic fish model based on Esox lucius. Besides the improved actuation properties like higher torque servomotors and powerful electronics,the robotic fish has some innovative mechanical design to pursue diverse swimming modes and superior performance. Specifically, we introduced a ±50° yawing head joint that functions as the neck for enhancing turning ability. A pair of pectoral mechanisms with two DOFs per fin is constructed to achieve 3-D swimming and to enrich multiple pectoral motions. At the control level, an improved central pattern generator(CPG) model allowing for free adjustment of the phase relationship among outputs is employed to produce rhythmic signals of multimodal swimming. Extensive experiments were carried out to examine how characteristic parameters in CPGs including amplitude, frequency, and phase lag affect the swimming performance. As a result, the robotic fish successfully performed various locomotion actions such as forward swimming, backward swimming, turning, diving, surfacing, as well as three pectoral motions in the form of pitching, heaving, and heaving-pitching.We found that small phase lag between oscillating joints which means large propulsive body wave length and undulation width could lead to a faster swimming in body and/or caudal fin(BCF) locomotion. | WU ZhengXing YU JunZhi SU ZongShuai TAN Min LI ZhenLong | 2015 | Science China(Information Sciences)2015，58，5： | 11 |
| 2 | 基于Android平台的智能家居系统设计显示文摘针对传统智能家居系统中存在的灵活性差、不易推广、功能单一、维护成本高等缺点,本文采用基于Android平台的智能家居系统设计方案,以Android智能终端作为客户端,以搭建Linux操作系统的ARM9微处理器作为服务器,以Zigbee技术构建内部网络,最终实现远程控制智能家居,并实时显示内部环境信息。 | 李琪 秦会斌 杨永舒 张雄 屈力扬 | 2014 | 电子设计工程2014，22，24： | 9 |
| 3 | Ergodic secrecy rate of two-user MISO interference channels with statistical CSI显示文摘This paper considers a two-user multiple-input single-output(MISO) interference channel with confidential messages(IFC-CM), where the beamforming vectors at the two transmitters are jointly optimized using the closed-form Pareto-optimal parameterization. We prove that artificial noise cannot improve the secrecy rate performance, and coordinated beamforming is secrecy-rate optimal which is achieved by agreeing on the parameters between the two transmitters. We analyze the feasible set of the beamforming parameters that guarantees positiveness of the secrecy rates when the transmitters know only statistical CSI, and then analysis in the ergodic secrecy rate region is discussed. More importantly, we derive the closed form of the ergodic secrecy rates and illustrate the Pareto-optimal structure of the beamforming vectors. | FEI ZeSong NI JiQing ZHAO Di XING ChengWen WANG NiWei KUANG JingMing | 2014 | Science China(Information Sciences)2014，57，10： | 7 |
| 4 | Survivability-oriented optimal node density for randomly deployed wireless sensor networks显示文摘The survivability is usually critical for wireless sensor networks,which are often deployed in the unattended harsh environment.Lots of technical schemes to improve the survivability depend on the redundant resources of the sensor networks.The amount of resources is usually determined by the node density during the deployment phase.For the random deployment and random node failures,the quantitative relation between the survivability and the node density is studied.Based on the conditional survivability,the node density to meet the required survivability level is presented.Finally,the survivability for unpredictable failures and the optimal node density to maximize the price–performance ratio are also discussed. | HUANGFU Wei ZHANG ZhongShan CHAI XiaoMeng LONG KePing | 2014 | Science China(Information Sciences)2014，57，2： | 5 |
| 5 | Physical layer security via maximal ratio combining and relay selection over Rayleigh fading channels显示文摘In this paper, the impact of both maximal ratio combining(MRC) and relay selection on the physical layer security in wireless communication systems is investigated by analyzing critical issues such as the probability characteristics of the legitimate receiver(Bob) and malicious eavesdropper(Eve)'s end-to-end signal-to-noise ratio(SNR), the secrecy outage probability and the average secrecy channel capacity over Rayleigh fading Channel, etc. Unlike the conventional physical layer security schemes, we assume that Bob receives its data from both the relay and the source via cooperative relay, provided that MRC is employed at the receiver.Particularly, compared to the conventional MRC methods, the proposed method is capable of achieving a higher spatial diversity order by performing relay selection, as validated by performing the theoretical analysis as well as numerical simulation. Furthermore, the closed-form expressions in terms of secrecy outage probability and average secrecy capacity are all consistent with the numerical results. Finally, the proposed scheme may be substantially affected by a number of parameters such as the number of relays, the SNR of links and the ratio of main-to-eavesdropper ratio(MER) λME. | Bin ZHONG Minggang WU Tong LI Zhongshan ZHANG | 2016 | Science China(Information Sciences)2016，59，6： | 5 |
| 6 | Optimal pilots design for frequency offsets and channel estimation in OFDM modulated single frequency networks显示文摘Optimal pilot design and placement for both the frequency offsets and channel estimation in Orthogonal Frequency-Division Multiplexing modulated Single Frequency Network are treated.Unlike the conventional frequency-domain filter-based algorithms,the proposed pilot of each transmitter can always be demodulated at the receiver even if the received pilots of multiple transmitters are totally overlapped.Although the channel state information is needed in designing the proposed pilot for carrier frequency offset(CFO)estimation,the performance of the proposed CFO estimation is robust to the channel estimation error.The optimal pilot as well as the Least-Squares(LS)channel estimator is also proposed,and the pilot for channel estimation is always a constant-modulus.A joint frequency offset and channel estimation scheme is also proposed,and the transmitters can adaptively optimize their pilots in the successive transmissions using the estimation results feedback in the former transmission.Simulation results demonstrate the performance of the proposed algorithm in terms of frequency offset and channel estimation accuracies.Since multiple copies of the same information can be received at each receiver,some combining technologies such as equal gain combining(EGC)or maximal ratio combining(MRC)can be applied at the receiver to improve the receiving diversity gain.Numerical results show that in a scenario of two transmitters with a Signal-to-Noise Ratio of 20 dB,the Bit Error Rate(BER)of1.5×10-4(or 1×10-4)can be obtained at the receiver using EGC(or MRC),and this BER performance can be improved to be 4×10-6for EGC(or 2×10-6for MRC)by considering three co-receiver transmitters. | LI Yang XU Xu ZHANG DanDan ZHANG ZhongShan LONG KePing | 2014 | Science China(Information Sciences)2014，57，4： | 5 |
| 7 | QoE-driven resource allocation for mobile IP services in wireless network显示文摘In this study, quality of experience(QoE)-driven resource allocation for multi-applications in Internet Protocol(IP)-based wireless networks is studied. Considering that the mean opinion score(MOS) summation maximization problem is not fair to satisfy heterogeneous users' QoE with various mobile applications, we apply multi-objective optimization method to maximize each user's MOS utility. At the beginning of this work, the relationship between MOS utility and user transmission rate for three multimedia applications, that is, File Download, Internet Protocol Television, and Voice over Internet Protocol are discussed. However, the relations under diverse evaluation models are quite different and users in various mobile applications have different requirements, which make the optimization problem difficult to solve. To meet each user's minimum rate requirement,the idea of Nash bargaining solution is applied in the Hungarian-based subcarrier assignment problem. Then to simplify the power allocation problem, the concept of equivalent channel is introduced. Further by applying the tolerance membership function, we develop a fuzzy Max-Min decision model for generating an optimal power allocation solution. Simulation results demonstrate the satisfying characteristics of the proposed algorithm in terms of MOS utility and average data rate. | FEI ZeSong XING ChengWen LI Na | 2015 | Science China(Information Sciences)2015，58，1： | 3 |
| 8 | A secure routing scheme based on social network analysis in wireless mesh networks显示文摘As an extension of wireless ad hoc and sensor networks, wireless mesh networks(WMNs) are employed as an emerging key solution for wireless broadband connectivity improvement. Due to the lack of physical security guarantees, WMNs are susceptible to various kinds of attack. In this paper, we focus on node social selfish attack, which decreases network performance significantly. Since this type of attack is not obvious to detect, we propose a security routing scheme based on social network and reputation evaluation to solve this attack issue. First, we present a dynamic reputation model to evaluate a node's routing behavior, from which we can identify selfish attacks and selfish nodes. Furthermore, a social characteristic evaluation model is studied to evaluate the social relationship among nodes. Groups are built based on the similarity of node social status and we can get a secure routing based on these social groups of nodes. In addition, in our scheme, nodes are encouraged to enter into multiple groups and friend nodes are recommended to join into groups to reduce the possibility of isolated nodes. Simulation results demonstrate that our scheme is able to reflect node security status, and routings are chosen and adjusted according to security status timely and accurately so that the safety and reliability of routing are improved. | Yao YU Zhaolong NING Lei GUO | 2016 | Science China Earth Sciences2016，59，12： | 2 |
| 9 | HMM改进Ad hoc网络延时的模型及抗毁性研究显示文摘为了更高效地处理无线移动自组织(Ad hoc)网络中的延时问题,采用了隐马尔科夫模型(HMM)进行移动方位的评估。HMM求解实现了Ad网络3个基本问题的求解,设计了移动节点观察的模型,MATLAB仿真表明参数值完全正确,符合观察要求。对模型进行抗毁性试验,网络的连通度较好,表明了抗毁性较强;节点最多发生在公共区域,表明网络连通性比较强。这一研究对于Ad hoc网络实际应用的拓展具有一定的价值。 | 吴勇翀 周艳华 | 2014 | 电子技术应用2014，40，10： | 1 |
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