A novel secure communication approach via chaotic masking is proposed. At the transmitter, a message sequence is added to a chaotic masking sequence and is,at the same time, also involved in the generation of the mask...A novel secure communication approach via chaotic masking is proposed. At the transmitter, a message sequence is added to a chaotic masking sequence and is,at the same time, also involved in the generation of the masking sequence. At the receiver, a non dynamical system which adopts the same nonlinear functions as what is adopted at transmitter is used to retrieve the masking sequence from the received signal and then the message sequence is recovered through subtraction. The results of the theoretical analysis and computer simulation show that the chaotic digital secure communication system presented in this paper has the fine security, high reliability and can be implemented easily.展开更多
Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of sh...Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of short-range communication,we devise a series of distributed power control(DPC) schemes for energy conservation(EC)and enhancement of radio resource utilization in the hybrid system.Firstly,a constrained opportunistic power control model is built up to take advantage of the interference avoidance methodology in the presence of service requirement and power constraint.Then,biasing scheme and admission control are added to evade ineffective power consumption and maintain the feasibility of the system.Upon feasibility,a non-cooperative game is further formulated to exploit the profit in EC with minor influence on spectral efficiency(SE).The convergence of the DPC schemes is validated and their performance is confirmed via simulation results.展开更多
The Nigerian power sector is faced with poorly organized billing and consumer relations management. Tariff billing and collection has been a big problem in some community in Nigeria even with the introduction of prepa...The Nigerian power sector is faced with poorly organized billing and consumer relations management. Tariff billing and collection has been a big problem in some community in Nigeria even with the introduction of prepaid meters. The process of payment is cumbersome and stressful as consumers have to go and pay in banks and then take tellers to power utility office to confirm their power bills payment before they can recharge their cards. The major purpose of this work is to design and implement a convenient, cashless, automated and transparent electricity metering, billing and payment system. This project combines the power electronic meter with a communications network which in this case is a GSM （global system for mobile） network. Remote electricity billing is a unique concept, in which the electricity board can collect the consumed units＇ data from consumer on mobile phone using GSM network. A unique property of this system is that, the electricity board can disconnect or reconnect consumers from remote location through the mobile phone. As this project works on GSM network, the system can be controlled from any part of the country.展开更多
Over the last 45 years, the development of backbone telecommunications systems and construction of strategic oil and gas pipelines has spanned tens of thousands ofkilometres in harsh environments （arctic to tropical,...Over the last 45 years, the development of backbone telecommunications systems and construction of strategic oil and gas pipelines has spanned tens of thousands ofkilometres in harsh environments （arctic to tropical, unmanned or developing areas）. As the vast majority of these areas are without an electrical power lines infrastructure, the need arose for a highly reliable and maintenance-free power supply to allow the continuous operations of these projects. ORC （Organic Rankine Cycle） based on CCVT （closed cycle vapor turbogenerator） was specially developed for the special requirements. The paper presents the CCVT and its mode of operation, design criteria and case studies in projects implemented in the last 45 years.展开更多
文摘A novel secure communication approach via chaotic masking is proposed. At the transmitter, a message sequence is added to a chaotic masking sequence and is,at the same time, also involved in the generation of the masking sequence. At the receiver, a non dynamical system which adopts the same nonlinear functions as what is adopted at transmitter is used to retrieve the masking sequence from the received signal and then the message sequence is recovered through subtraction. The results of the theoretical analysis and computer simulation show that the chaotic digital secure communication system presented in this paper has the fine security, high reliability and can be implemented easily.
基金This work has been partly supported by National Natural Science Foundation of China，National High Technology Research and Development Program of China (863 Program)
文摘Device-to-Device(D2D) communication has been proposed as a promising implementation of green communication to benefit the existed cellular network.In order to limit cross-tier interference while explore the gain of short-range communication,we devise a series of distributed power control(DPC) schemes for energy conservation(EC)and enhancement of radio resource utilization in the hybrid system.Firstly,a constrained opportunistic power control model is built up to take advantage of the interference avoidance methodology in the presence of service requirement and power constraint.Then,biasing scheme and admission control are added to evade ineffective power consumption and maintain the feasibility of the system.Upon feasibility,a non-cooperative game is further formulated to exploit the profit in EC with minor influence on spectral efficiency(SE).The convergence of the DPC schemes is validated and their performance is confirmed via simulation results.
文摘The Nigerian power sector is faced with poorly organized billing and consumer relations management. Tariff billing and collection has been a big problem in some community in Nigeria even with the introduction of prepaid meters. The process of payment is cumbersome and stressful as consumers have to go and pay in banks and then take tellers to power utility office to confirm their power bills payment before they can recharge their cards. The major purpose of this work is to design and implement a convenient, cashless, automated and transparent electricity metering, billing and payment system. This project combines the power electronic meter with a communications network which in this case is a GSM （global system for mobile） network. Remote electricity billing is a unique concept, in which the electricity board can collect the consumed units＇ data from consumer on mobile phone using GSM network. A unique property of this system is that, the electricity board can disconnect or reconnect consumers from remote location through the mobile phone. As this project works on GSM network, the system can be controlled from any part of the country.
文摘Over the last 45 years, the development of backbone telecommunications systems and construction of strategic oil and gas pipelines has spanned tens of thousands ofkilometres in harsh environments （arctic to tropical, unmanned or developing areas）. As the vast majority of these areas are without an electrical power lines infrastructure, the need arose for a highly reliable and maintenance-free power supply to allow the continuous operations of these projects. ORC （Organic Rankine Cycle） based on CCVT （closed cycle vapor turbogenerator） was specially developed for the special requirements. The paper presents the CCVT and its mode of operation, design criteria and case studies in projects implemented in the last 45 years.
