检索结果-南通市图书馆

Simplified Protocol of Quantum Teleportation

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Quantum Information Science 2018年第3期8卷 107-120页

作者： Mario Mastriani Quantum Optics Department Merx Lab Aventura FL USA Applied Physics Group Merx-FI Miami FL USA

A simplified version of the quantum teleportation protocol is presented in here. Its experimental confirmation will have deep implications for a better understanding of Quantum Entanglement with a particular projectio... 详细信息

关键词： Bell States BSM EPR Pairs LOCC No-Cloning Theorem Quantum communications Quantum Entanglement Quantum Teleportation

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

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

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

Reduced Ecological Footprints of Modern Facilities Introducing the Implementation of Advanced Wireless Technologies, and Human Resources’ Benefits

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

communications and Network 2018年第1期10卷 11-29页

作者： Spyridon K. Chronopoulos Evangelia I. Kosma Dionysios Tafiadis Dimitrios Dimopoulos Vasilis Raptis Evaggelos C. Karvounis Pantelis Angelidis Panos Kostarakis Physics Department Electronics-Telecommunications and Applications Laboratory University of Ioannina Ioannina Greece Department of Informatics and Telecommunications Engineering University of Western Macedonia Kozani Greece Department of Computer Engineering Technological Educational Institute of Epirus Epirus Greece Faculty of Medicine School of Health Sciences University of Thessaly Larissa Greece Mihail Aggelou 18 Ioannina Greece Department of Speech & Language Therapy Technological Educational Institute of Epirus Ioannina Greece “G. Hatzikosta” General Hospital of Ioannina Ioannina Greece

The necessity of lowering the mean power consumption of various facilities, due to the lack of their enormous future energy needs, led to an ongoing advance of various technologies. These technologies have been oriented towards the concept of a Reduced Ecological Footprint. Massive structures (such as building complexes and hospitals) have been redesigned and upgraded;many interior designs have been dramatically altered while new electronic devices are constantly being produced in order to revolutionize a long term perspective towards a “Green Planet” while they exhibit astonishing signal processing. Consequently, an enormous technology already exists which needs to be properly combined to a proposed methodology and to new ideas relevant to systems’ administration through automatic wireless control. This paper intends to reduce the gap between design and realization of the aforementioned research. Consequently, the primary contribution of this research is the proposal of a complete design protocol with minimized defects relevant to Reduced Ecological Footprints of Facilities (REFF) along with its beneficial advantages relevant to providing a healthy and productive work environment. This protocol consists of four main parts which are 1) the main key points-guidelines, 2) its objectives, 3) the know-how methodology for implementation in existing installations and 4) the description of the imminent benefits in workforce/human resources.

关键词： Reduced Ecological Footprint Energy Needs Wireless communications Sensors Workforce Productivity

Chang'e 4's Relay Satellite Bridging Earth and Moon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Aerospace China 2019年第2期20卷 40-45页

作者： YU Guobin Lunar Exploration and Space Program Center CNSA Beijing 100048

The far side of the moon is a unique place for some scientific ***'e 4 is a Chinese lunar far side landing exploration *** communication satellite,named as Queqiao,is an important and innovative part of Chang'e 4 *** can provide relay communication to the lander and the rover operating on the lunar far side to maintain their contacts with *** was launched by LM-4C launch vehicle at the Xichang Satellite Launch Center on May 21,*** five precise orbit controls and a journey of more than 20 days,Queqiao inserted into final halo mission orbit around Earth-moon libration point 2,located about 65,000 km beyond the *** is the world's first communication satellite operating in that *** to now,Queqiao worked very well and provided reliable,continuous communication relay service for the lander and the rover to ensure the mission success of Chang'e 4 exploration *** Queqiao,the lander and the rover were controlled to work by ground stations and obtained a great amount of scientific *** mission overview,operation orbit selection,relay communication system design and flight profile were introduced in this article.

关键词： Chang'e 4 mission Queqiao lunar far side relay communications Earth-moon libration point 2

Resource Optimisation for 3rd Generation Partnership Project (3GPP) Long Term Evolution OFDMA Downlink Interface Air

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Wireless Engineering and Technology 2013年第4期4卷 188-197页

作者： Ayoola Akinloye Akinniranye Samson Adenle Oyetunji Federal University of Technology Akure Akure Nigeria MTN Nigeria

This Paper describes the system model of the developed optimisation scheme which is implemented using a simulation package known as MATLAB. The 3rd Generation Partnership Project (3GPP) Long Term Evolution standard for the downlink air interface, Orthogonal Frequency Division Multiple Access (OFDMA) was adopted. Frequency Selective Rayleigh fading channel is considered as a model for real life scenario of the LTE Evaluation, operating in 5 MHz downlink bandwidth of OFDMA parameters as proposed in the standard. Simulation results show that, the inherent characteristics of a communication channel can be exploited and combined with the robustness of OFDMA to optimally allocate the radio resources. The optimal channel assignment of the dynamic allocation scheme exploited in this work meets the set target of high data rate and spectral efficiency.

关键词： Communication Channels Wireless Mobile communications Noise OFDMA

OPTIMAL COHERENT DETECTION OF FSK SIGNALS WITH IMBALANCE AMPLITUDES IN THE PRESENCE OF COLORED GAUSSIAN NOISE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electronics(China) 2000年第4期17卷 331-337页

作者： Shen Yuehong Li Xingguo Yi Xiaoxin Qian Zuping(Nanjing Institute of communications Engineering, Nanjing 210016, China) (Nanjing University of Science and Technology, Nanjing 210094, China)

The problem of optimal coherent detection of frequency-shift keying (FSK) signals transmitted over an additive colored Gaussian noise channel with imbalance gains in different frequencies (IGDF-ACGN channel) is studied. The structure of the optimal coherent detector is derived. Theoretical analysis and computer simulation results show that the detector is optimal in either additive colored Gaussian noise environment or additive white Gaussian noise environment.

关键词： Digital modulation Digital demodulation Optimal detector Digital communications

Dual Band BPF Based on Parallel Coupled Lines Loaded by Open Stubs for Ku-Band Satellite Applications

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Electromagnetic Analysis and Applications 2019年第9期11卷 148-160页

作者： Ahmed S. I. Amar Osama M. A. Dardeer Abdelhaleem A. Zekry Electronics and Electrical Communication Engineering Department Faculty of Engineering Ain Shams University Cairo Egypt Electronics Research Institute El-Tahreer St. Dokki Giza Egypt

This paper presents a dual band Band Pass Filter (BPF) operating at both the downlink and uplink frequency bands for Ku-band satellite applications. The commonly used frequency band in mobile communications satellites is the Ku-band. These mobile satellite systems help connect remote regions, vehicles, ships, people and aircraft to other parts of the world and/or other mobile or stationary communications units, in addition to serving as navigation systems. The structure of the proposed filter is based on parallel coupled microstrip lines and four sections are used. Tuning the two operational bands can be achieved using two open-circuited stubs at the first and last sections of the parallel coupled microstrip lines. The proposed filter is adjusted to operate at 12.54 GHz and 14.14 GHz for downlink and uplink bands, respectively. The proposed dual band BPF is fabricated, measured, and good agreement is obtained between simulated and measured results.

关键词： BPF Single-Band Wide-Band Parallel Coupled Lines Mobile communications Satellite Transmitters

A Magnetically Levitated Precise Pointing Mechanism for Application to Optical Communication Terminals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optics and Photonics Journal 2012年第2期2卷 85-97页

作者： Thomas Edward Donaldson Frame Alexandre Alexandre Pechev Surrey Space Centre University of Surrey Guildford UK

Increasing data bandwidth requirements from spacecraft systems is beginning to pressure existing microwave communications systems. Free-Space optical communications allows for larger bandwidths for lower relative power consumption, smaller size and weight when compared to the microwave equivalent. However optical communication does have a formidable challenge that needs to be overcome before the advantages of the technology can be fully utilized. In order for the communication to be successful the transmitter and receiver terminals need to be pointed with a high accuracy (generally in the order of ≤10 μradians) for the duration of communication. In this paper we present a new concept for the precise pointing of optical communications terminals (termed the Precise Pointing Mechanism). In this new concept we combine the separate pointing mechanisms of a conventional optical terminal into a single mechanism, reducing the complexity and cost of the optical bench. This is achieved by electromagnetically actuating the whole telescope assembly in 6 degrees-of-freedom with an angular resolution of less than ±3 μradians within a 10 (Az. El.) field of view and linear resolution of ±2 μm. This paper presents the new pointing mechanism and discusses the modelling, simulation and experimental work undertaken using the bespoke engineering model developed.

关键词： Optical communications Magnetic Levitation Control Pointing Active Anti-Vibration

Tele-Protection Implementation Using IEEE 1588 Precision Time Protocol in Colombian High Power Substations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Power and Energy Engineering 2015年第4期3卷 23-28页

作者： Hermes Eslava Luis Alejandro Rojas Danny Pineda Universidad Distrital Bogotá Colombia Openlink Sistemas DE Redes DE Datos S.A.S Bogotá Colombia

Optical fiber has been used as typical physical transmission medium in Colombian high power substations for effective communication between substations and control centers. However, suita- ble transmissions of tele-protection services continues to be a challenging area in the electrical- supply sector since link stability as well as various performance tests suggest that link recurrence requirements still exhibit limitations when using Metroethernet networks in this context. At pre- sent, improvements have been achieved via proprietary protocols such as Mirrored Bits, which matches the performance of a tele-protection link transmission under normal operation conditions. However, this imposes commercial limitations on the Colombian electrical-supply sector since proprietary protocols hinder fair competition among manufacturers. This is the rationale behind conducting trials with precision time protocol as it is defined in IEEE 1588 standard. The main purpose is to validate whether, under real operation conditions, it is possible to substitute such tele-protection links via Metroethernet networks, yet considering a standard protocol that allows incorporating various pieces of equipment from different manufacturers into the system as well as providing common benefits derived from using this type of communication networks. The present work provides technical results obtained after conducting various simulated tele-trigger tests, including stress tests, where results-stability validation occurs through network-saturation simulations. These saturation conditions are achieved by incorporating additional traffic, which involves several switching events over link paths and permits validating tele-protection-response timing when specifically using IEEE 1588 precision time protocol. Based on the aforementioned reasons as well as on the resulting benefits, a series of laboratory tests have been defined in order to evaluate delay and availability on tele-protection services when

关键词： Metro Ethernet IEEE 1588 IEC 61850 Tele-Protection Effective communications Tele-Trigger Simulations