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Optimal Set of Multiple Relays and Distributed Self-Selection in Cooperative Networks

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Communications and Network 2013年第2期5卷 140-147页

作者： Xiaohua Li Chengyu Xiong Jeong Kyun Lee Department of Electrical and Computer Engineering State University of New York Binghamton USA

In this paper we derive analytically the optimal set of relays for the maximal destination signal-to-noise ratio (SNR) in a two-hop amplify-and-forward cooperative network with frequency-selective fading channels. Simple rules are derived to determine the optimal relays from all available candidates. Our results show that a node either participates in relaying with full power or does not participate in relaying at all, and that a node is a valid relay if and only if its SNR is higher than the optimal destination SNR. In addition, we develop a simple distributed algorithm for each node to determine whether participating in relaying by comparing its own SNR with the broadcasted destination SNR. This algorithm has extremely low overhead, and is shown to converge to the optimal solution fast and exactly within a finite number of iterations. The extremely high efficiency makes it especially suitable to time-varying mobile networks.

关键词： Cooperative Transmission amplify and Forward Relaying Signal to Noise Ratio Distributed Algorithm Linear-Fractional Programming

New Approach for Relay and Transceiver Design for Interference Alignment in MIMO Interference Channels

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Journal of Computer and Communications 2013年第3期1卷 1-7页

作者： Hossein Vaezy Vahid Tabataba Vakili Department of Electrical Engineering Iran University of Science and Technology Narmak Iran

Wireless relaying has been known to provide the improvements in link reliability, spectral efficiency, and coverage extension. In this paper, we use full duplex relays for Interference Alignment (IA) in K-users Interference Channel (IC) and show K Degrees of Freedom (DOF) is achievable. In first hop, relays receive signals from transmitters and forward them to receivers in second hop. Two iteratively algorithms are proposed for computing relays function, precoder, and decoder matrices. First algorithm minimizes leakage interference at receivers that has appropriate performance at high Signal to Noise Ratio (SNR) region. Furthermore, the second algorithm has better performance at low-mediate SNR. The performance of proposed algorithms are compared with other schemes and validated with simulation in terms of achieved sum rate.

关键词： Interference Alignment Degree of Freedom Multiple Input Multiple Output (MIMO) amplify and Forward (AF)

A New Method to Improve Performance of Cooperative Underwater Acoustic Wireless Sensor Networks via Frequency Controlled Transmission Based on Length of Data Links

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Wireless Sensor Network 2010年第5期2卷 381-389页

作者： Vahid Tabataba Vakily Mohammadjavad Jannati 不详

In this paper a new method to improve performance of cooperative underwater acoustic (UWA) sensor networks will be introduced. The method is based on controlling and optimizing carrier frequencies which are used in data links between network nods. In UWA channels Pathloss and noise power spectrum density (psd) are related to carrier frequency. Therefore, unlike radio communications, in UWA Communications signal to noise ratio (SNR) is related to frequency besides propagation link length. In such channels an optimum frequency in whole frequency band and link lengths cannot be found. In Cooperative transmission, transmitter sends one copy of transmitted data packets to relay node. Then relay depending on cooperation scheme, amplifies or decodes each data packet and retransmit it to destination. Receiver uses and combines both received signals to estimate transmitted data. This paper wants to propose a new method to decrease network power consumptions by controlling and sub-optimizing transmission frequency based on link length. For this purpose, underwater channel parameters is simulated and analyzed in 1km to 10km lengths (midrange channel). Then link lengths sub categorized and in each category, optimum frequency is computed. With these sub optimum frequencies, sensors and base station can adaptively control their carrier frequencies based on link length and decrease network’s power consumptions. Finally Different Cooperative transmission schemes “Decode and Forward (DF)” and “amplify and Forward (AF)”, are simulated in UWA wireless Sensor network with and without the new method. In receiver maximum ratio combiner (MRC) is used to combining received signals and making data estimations. Simulations show that the new method, called AFC cooperative UWA communication, can improve performance of underwater acoustic wireless sensor networks up to 40.14%.

关键词： Underwater Acoustic Communications Wireless Sensor Networks Cooperative Transmission Decode and Forward amplify and Forward

Association between LMNA mutation and familial and idiopathic dilated cardiomyopathy patients in Xinjiang

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China Medical Abstracts(Internal Medicine) 2014年第2期31卷 96-97页

作者：孙帅 Cardiac Pacing & Electrophy Div 1st Affil HospXinjiang Med Univ

Objective To explore the association between LMNA gene mutation and familiar dilated cardiomyopathy(DCM)(FDCM)and idiopathic DCM(IDCM)in Uygurs and Han people in Xinjiang *** Peripheral blood samples were collected fr... 详细信息

关键词： dilated cardiomyopathy mutation familial familiar sporadic sequenced amplify allele substitution

*** and erythrocyte function

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外科研究与新技术 1993年第2期 103-105页

930337 Polymerase chain reaction in alpha-thalassemia gene analysis and prenatal *** Xiaojun (文晓军),et al.

关键词： Polymerase erythrocyte globin anemia interleukin 文境 Nanning minutes allele amplify

THE EFFECT OF AMPLIFICATION OF THE MOIST-SPECIFIC AVAILABLE ENERGY ON THE SIGNALS OF NON-LOCAL HEAVY RAINFALL

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Chinese Science Bulletin 1984年第8期29卷 1067-1071页

作者：吴宝俊 Institute of Weather and Climate Research Academy of Meteorological Science Beijing

As may be imagined, a certain physical parameter will be of great benefit to the weather analysis and forecasting if it can amplify the signals reflecting the changes of weather and suppress other disturbances.

关键词： weather reflecting amplify LOCAL suppress forecasting figures benefit keeping illustration

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NEOPLASMS

China Medical Abstracts(Internal Medicine) 2004年第2期21卷 77-78页

2004193 Quantitation and detection of deletion in tumor mitochondrial DNA by microarray *** Chengbo (韩琤波), et al. Tumor Instit, 1st Affili Hosp, China Med Univ, Shenyang 110001. Chin J Oncol 2004;26(1):***: To deve... 详细信息

关键词： deletion mitochondrial DNA Polymerase alteration NEOPLASMS tumorigenesis staining amplify 韩玲

Joint Power Allocation and Beamforming for Cooperative Networks

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International Journal of Communications, Network and System Sciences 2011年第7期4卷 447-451页

作者： Sondes Maadi Noureddine Hamdi 不详

In this paper, we investigate power allocation problem with the use of transmit beamforming in a dual hop MISO (multiple input single output) relay channel. We consider either amplify and forward (AF) or decode and forward (DF) cooperative protocols at the relay and optimize the power allocated to the relay and the source, under total transmit power constraint, to minimize the bit error rate (BER) of relaying system. Cooperative communication is viewed as a method for increasing diversity gain and reducing end to end path loss. The use of relay can create a virtual antenna array so that it allows users to exploit the advantages of multiple input multiple output (MIMO) techniques. In this work, we solve cooperative ratio, which is defined as the ratio power used for cooperative transmission over the total power. This approach is then compared to an equal power assignment method and its performance enhancement is verified by simulation results.

关键词： amplify and Forward Decode and Forward Transmit Beamforming Power Allocation MISO Cooperative Communication

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关于健全和完善社会保障财政制度的思考

关于健全和完善社会保障财政制度的思考

作者：徐庆丰东北师范大学

学位级别：硕士

健全的社会保障制度是各国政府社会政策的重要组成部分,是社会主义市场经济体制的重要支柱,关系改革、发展、稳定的全局。而我国现阶段社会保障制度改革和社会保障事业发展所遇到的诸多障碍中,最需迫切克服者莫过于资金短缺。充足的社... 详细信息

健全的社会保障制度是各国政府社会政策的重要组成部分,是社会主义市场经济体制的重要支柱,关系改革、发展、稳定的全局。而我国现阶段社会保障制度改革和社会保障事业发展所遇到的诸多障碍中,最需迫切克服者莫过于资金短缺。充足的社会保障基金是社会保障制度赖以存在和运行的物质基础。一段时间以来,理论界在我国社会保障基金问题上的主流观点是为了避免“福利病”和几乎必然出现的人口老龄化问题,应该主要依靠“自我保障”实现经济中的激励安排。这种典型的新古典思想体现在政策上,以个人储蓄为基本特征的基金制度更适合中国当前国有企业改革现状。另一方面,在经历了严重的养老保险、医疗保险供求平衡所造成的潜在社会问题后,部分理论和实践工作者提出了继续依靠财政安排、国家必须承担更大改革成本的思路。有学者在理论上彻底否定了基金制的效率假说,证明了纯粹的个人自我保险不仅不能促进经济效率,反而造成过度储蓄、利率下降,居民未来收入下降等一系列宏观经济后果;相反,依靠国家财政支出实现的社会保障安排却可以增进效率。这就从理论角度给中国社会保障制度建设提供了全新思路。本文在上述理论研究的基础上,大量借鉴经济学研究成果,从法学角度将社会保障与财政联系起来思考,探讨财政支持社会保障的制度,并对社会保障财政制度作出若干制度设计。首先阐述了社会保障财政制度的内涵及建立的必要性,明确了社会保障财政责任的界定;又总结了我国社会保障财政制度的基本情况和存在的主要问题;最后提出了完善我国社会保障财政制度的若干对策。

关键词： amplify improve social security finance system