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Vehicular ad hoc networks (VANETs) have recently received considerable attentions for both safety and commercial applications. In this paper, we address popular content distribution (PCD) in VANETs, in which a popular file is downloaded by a group of on-board units (OBUs) passing by a roadside unit (RSU). Due to high speeds and channel fadings, the OBUs may not finish downloading the entire file from...
We consider a cognitive radio network in which multiple pairs of secondary users (SUs) communicate by a oneway relay node over orthogonal channels with the existence of an eavesdropper close to the destination. The transmit power of the relay needs efficient distribution for maximizing the sum secrecy rate of the SU pairs, meanwhile satisfying the interference constraint at the single primary user...
It has been well recognized that the capacity of a wireless system is usually limited because of intracell interference and intercell interference (ICI), and many technologies have been used to combat against them in different systems. Here, we consider a closed-loop wireless network with a limited feedback rate. In such networks, channel state information (CSI) feedback has become a well recognized...
Grasp planning is a crucial problem for a service robot. It affects the quality of the interaction between robot and environment. This paper presents a grasp planning system for the service robot FRIEND3 in manipulate book. The system consists of three parts: generate prehensile points, generate grasp strategies and grasp memory. The prehensile points are generated from the primitives of the object...
In this paper, we analyze the protocol architecture of Wireless Sensor Networks (WSNs) and carrying networks, and propose a connection scheme based on gateway, which is suitable to the integration of these two networks. According to the characteristics of these gateways, we put forward the concept of end-to-end connection, give the address mapping scheme to the gateway and design a simple gateway...
For high-speed motor unit, in particular, it is very important to accurately predict natural frequencies and vibration modes of shafting at the design stage so as to minimize the likelihood of failure. Finite element (FE) analysis and experimental measurements are used to establish the natural frequencies and modes of multi-span shafting coupled by flexible coupling, and to assess the influence of...
In this paper, we consider a multiuser multi-antenna two-way relay system in which multiple pairs of partners communicate via a single relay node and share its total transmit power. In order to allocate the limited power with both efficiency and fairness, we introduce a sequential second price auction as a mechanism to achieve such goals. First, we provide the system model and formulate the channel...
In this paper, we consider a cognitive radio network in which multiple pairs of secondary users (SUs) exchange their information over two-way relay orthogonal channels with the existence of an eavesdropper. The SU pairs share the same frequency band with a primary user (PU) by satisfying the interference power constraint, and the eavesdropper can listen to all the frequency bands. Our goal is to maximize...
Based on the T-type equivalent circuit model of loosely coupled transformer, the theory of series-series (SS) resonant inductively coupled power transfer (ICPT) system was analyzed. By researching the principle of ICPT system working at zero voltage switch (ZVS) mode, the condition for realizing ZVS mode was got that the load resistance should be bigger than its critical value. According to the characteristic...
Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. Since the micro-turbine cannot be self started, the PM generator has to operate as a motor for the system staring, which needs...
Recently more attention has been paid to the distributed power systems due to their high flexibility and reliability. The high speed permanent magnet (PM) generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency...
Is it possible to explain the chemistry of the human organism using just seven molecules? The authors show how it can be done, while explaining how many astonishing and useful things there are to be found in the wonderful world of molecules.
The 3D finite element analysis (FEA) is used to establish the natural frequencies and vibration modes of the magnetic bearing-rotor system of high-speed machine and to define bearing stiffness of 3D-FEA model by exciting experiment. The critical speeds calculated by the method of FEA consistent with tested results of a high speed permanent magnet (PM). The study shows that the magnetic bearings introduce...
Permanent magnet (PM) machine is especially being employed in high speed machines due to its simple structure and high power density. Nowadays, the sintered neodymium-iron-boron (Nd-Fe-B) material is used in most of PM machines. This kind of PM material has large compression strength but small tensile strength, and can not withstand the large centrifugal force due to the high rotation speed. A nonmagnetic...
High speed permanent magnet generator driven by micro-turbine has been widely investigated since it has small size, high efficiency and power density. The output high frequency AC power of the high speed PM generator needs to be converted into the AC power with constant frequency and voltage using AC/DC/AC converter. In order to reduce the current harmonics of high speed generator produced by the...
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