Effects of Optical Beams on MIMO Visible Light Communication Channel Characteristics

Under 5G envision, for pushing visible light communication (VLC) channel model evolution to various non-Lambertian beams, this paper introduces the typical commercial non-Lambertian beams, such as Luxeon rebel and side emitter, into the conventional analytical VLC channel model. The numerical results illustrate that the non-Lambertian beams can significantly affect the VLC channel frequency response characteristics. Compared with the traditional Lambertian beam, Side Emitter optical beam could naturally bring up to about 56.8% VLC multi input multi output channel capacity deviation, which objectively opens a new discussion dimension for enhancing VLC transmission performance.

Can Wavelet Transform Detect LDDoS Abnormal Traffic in Multipath TCP Transmission System?

With the rapid development of mobile Internet technology and multihost terminal devices, multipath transmission protocol has been widely concerned. Among them, multipath TCP (MPTCP) has become a hot research protocol in recent years because of its good transmission performance and Internet compatibility. Due to the increasing power of Low-Rate Distributed Denial of Service (LDDoS) attack, the network security situation is becoming increasingly serious. The robustness of MPTCP network has become an urgent performance index to improve. Therefore, it is very necessary to detect LDDoS abnormal traffic timely and effectively in the transmission system based on MPTCP. This paper tries to use wavelet transform technology to decompose and reconstruct network traffic and find a detection method of LDDoS abnormal traffic in the MPTCP transmission system. The experimental results show that in the MPTCP transmission system, the signal processing technology based on wavelet transform can realize the identification of LDDoS abnormal traffic. It indicates a direction worth further exploration for the detection and defense of the LDDoS attack.

The Optimal Carrier-Secret Ratio for Wireless Covert Channels Based on Constellation Shaping Modulation

Wireless covert communication is an emerging communication technique that prevents eavesdropping. This paper considers the bit error ratio (BER) problem of covert communication based on constellation shaping modulation (CSM). The impact of carrier-secret ratio (CSR) on BER is studied and the approximate solution of optimal CSR is obtained. Then, we extended the conclusion to typical communication scenarios with one and more relays where the undetectability and reliability were analyzed and inspected. It is proved that there also exists the optimal CSR in scenarios with relays. Additionally, it is found that the undetectability under the constraints of constant total power depends on the eavesdropper’s position, and we found an undetectability deterioration area (UDA) in the scenario of relays. Simulation results show the existence of optimal CSR and its impact on transmission performance.

Multi-motor Drive Control Method of Upper-Retort-Robot Based on Machine Vision

A research on the multi-motor drive control method of the upper-retort-robot based on machine vision is proposed in this paper for wine brewing automation to suffice the demand of military areas situated in cold regions as wine is recommended to keep the body temperature of soldiers normal in highly cold regions of China. Based on machine vision, the target is converted into an image signal by an image pickup device and is sent to the image processing system. The pixel distribution, brightness, color and other information are converted into digital signals and the target features are extracted to control the actions of the field equipment. The Monte-Carlo method is exploited to randomly generate joint variables within the variation range of each joint. The positive aspects of kinematics model are utilized and the working space of the upper-retort-robot is calculated using multi-motor drive control method. The multi-motor drive compensates the harmonic ripple torque, and establishes the fault-tolerant automatic control of the system to maintain quality of the liquor. The experimental results show that the robot arm can reach at any position in the barrel within the defined range. The robot will work in an automated mode to control the quality of the liquor. The transmission performance of the robot can meet the requirements of the automated quality control of the liquor during processing of wine from grapes. The results are obtained for robot transmission performance and robot dexterity which proves the robustness and viability of the proposed multi-motor drive control method (MMDCM).

‘Their lamentable hone’

This chapter examines the sounds and voices of caoineadh (keen), an Irish Gaelic form of lament, associated with performance by women as part of the burial process and with the female expression of political protest. It opens with a study of the sounds of caoineadh, setting non-Gaelic, often travellers’ accounts, from the 1570s through to the 1770s, in context with the genre’s long-established formal conventions of metre, rhyme, and theme. This is grounded in a critical history of the genre and illustrated with examples from the seventeenth and eighteenth centuries. Questions of oral transmission, performance, textual authority, and authenticity are crucial to the history of the surviving texts and, therefore, central to the discussion.