TP212.14//TN25 2003042923单光纤多参数的同步传输与接收=Multi-parameter transmittingand receiving synchronously with a single optical fiber[刊,中]/温淑慧(燕山大学电气工程学院.河北,秦皇岛(066004))∥传感技术学报.-2002,15(...TP212.14//TN25 2003042923单光纤多参数的同步传输与接收=Multi-parameter transmittingand receiving synchronously with a single optical fiber[刊,中]/温淑慧(燕山大学电气工程学院.河北,秦皇岛(066004))∥传感技术学报.-2002,15(4).-400-402介绍了一种在油罐液位测量中通过单光纤分时传输多参数信号的方法,实现了信号的分时合成与接收,有效地解决了信号发射端与接收端的同步问题,从而提高了液位测量精度。图4参2(李士范)展开更多
One key advantage of 4G OFDM system is the relatively simple receiver implementation due to the orthogonal resource allocation.However,from sum-capacity and spectral efficiency points of view,orthogonal systems are ne...One key advantage of 4G OFDM system is the relatively simple receiver implementation due to the orthogonal resource allocation.However,from sum-capacity and spectral efficiency points of view,orthogonal systems are never the achieving schemes.With the rapid development of mobile communication systems,a novel concept of non-orthogonal transmission for 5G mobile communications has attracted researches all around the world.In this trend,many new multiple access schemes and waveform modulation technologies were proposed.In this paper,some promising ones of them were discussed which include Non-orthogonal Multiple Access(NOMA),Sparse Code Multiple Access(SCMA),Multi-user Shared Access(MUSA),Pattern Division Multiple Access(PDMA)and some main new waveforms including Filter-bank based Multicarrier(FBMC),Universal Filtered Multi-Carrier(UFMC),Generalized Frequency Division Multiplexing(GFDM).By analyzing and comparing features of these technologies,a research direction of guiding on future 5G multiple access and waveform are given.展开更多
Many efforts have been made to develop time division multiple access （TDMA） slots allocation in a multi-hop converge-cast wireless sensor network （WSN）, however, most of them either use complex algorithm or concer...Many efforts have been made to develop time division multiple access （TDMA） slots allocation in a multi-hop converge-cast wireless sensor network （WSN）, however, most of them either use complex algorithm or concern frames only without simultaneous transmission in a single slot. In this paper, we present a timeslot assignment scheme for cluster-tree-based TDMA WSN, co：＇ering three frequently used working modes in practical applications. The shortest frame formed can guarantee real-time conununication and is also facilitated for message and slot integration, since timeslots allocated to a single node are continuous. During allocation processes, the algorithms are distributed and light-weighted. The experiment resulted from a WSN prototype system shows that our scheme can achieve a good reliability.展开更多
Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of th...Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of the WiMedia protocol.In this work,we propose a multi-hop QoS routing protocol to enable WiMedia devices to transmit real-time data to devices that are located out of the transmission range.The proposed routing protocol is a hybrid algorithm,which mixes the table-driven and on-demand routing algorithms,searching one or more routes according to the number of hops to a destination device.WiMedia MAC is potentially capable of learning the existence of neighbor devices by using a beacon frame.By utilizing the neighbors' information,all devices can create routing entries for devices within 2-hops periodically.For devices beyond the 2-hop range,the newly designed on-demand routing algorithm is applied to multi-hop routing.If a routing entry for a destination device is not listed in the routing table,the source device sends a request packet to 2-hop range devices which could be found in the routing table.Since every device maintains routing entries for 2-hop range devices in the routing table,the request packet is replied in advance before its arrival at the destination device.Also,to decide the optimal route for a destination device,the number of medium access slots(MASs),received signal strength indicator(RSSI)and hop count are utilized to establish a QoS-enabled routing table.We perform ns-2 simulation to investigate the performance of the proposed routing protocol with AODV and DSDV.The simulation results show that the proposed protocol has better throughput and lower overhead than other protocols.展开更多
The time-resolved photoluminescence and steady photoluminescence (TRPL and PL) spectra on self-assembled InAs/GaAs quantum dots (QDs) are investigated. By depositing GaAs/InAs short period superlattices (SLs), 1.48μm...The time-resolved photoluminescence and steady photoluminescence (TRPL and PL) spectra on self-assembled InAs/GaAs quantum dots (QDs) are investigated. By depositing GaAs/InAs short period superlattices (SLs), 1.48μm emission is obtained at room temperature. Temperature dependent PL measurements show that the PL intensity of the emission is very steady. It decays only to half as the temperature increases from 15K to room temperature, while at the same time, the intensity of the other emission decreases by a factor of 5 orders of magnitude. These two emissions are attributed to large-size QDs and short period superlattices (SLs), respectively. Large-size QDs are easier to capture and confine carriers, which benefits the lifetime of PL, and therefore makes the emission intensity insensitive to the temperature.展开更多
This paper investigates the vibration characteristics of diesel engine cylinder heads by means of the time series method. With the concept of "Assumed System",the vibration transfer function of real cylinder...This paper investigates the vibration characteristics of diesel engine cylinder heads by means of the time series method. With the concept of "Assumed System",the vibration transfer function of real cylinder head structures is established using the autoregressive-moving average models(ARMA models) of cylinder head surface vibration signals. Then this transfer function is successfully used to reconstruct the gas pressure trace inside the cylinder from measured cylinder head vibration signals. This offers an effective means for diesel engine cylinder pressure detection and condition monitoring.展开更多
Metallic ring-shaped nanotube arrays are proposed and its optical transmission properties are studied by using finite-difference time-domain （FDTD） method. Compared with the transmission spectra of conventional circ...Metallic ring-shaped nanotube arrays are proposed and its optical transmission properties are studied by using finite-difference time-domain （FDTD） method. Compared with the transmission spectra of conventional circular nanotube arrays, two photonic band gaps are emerged in the transmission spectra offing-shaped nanotube arrays, the two band gaps and transmission spectra are adjusted by the length, inner radius, intertube spacing and the dielectric constants of the core and embedding medium, and magnitude modification, redshift and blueshift of the resonance modes are observed. A metallic ring-shaped nanotube arrays for subwavelength band-stop filter in the range of visible light can be achieved. To understand its physical origin, field-interference mechanism was suggested by the field distributions. The proposed nanostructures and results may have great potential applications in subwavelength near-field optics.展开更多
文摘TP212.14//TN25 2003042923单光纤多参数的同步传输与接收=Multi-parameter transmittingand receiving synchronously with a single optical fiber[刊,中]/温淑慧(燕山大学电气工程学院.河北,秦皇岛(066004))∥传感技术学报.-2002,15(4).-400-402介绍了一种在油罐液位测量中通过单光纤分时传输多参数信号的方法,实现了信号的分时合成与接收,有效地解决了信号发射端与接收端的同步问题,从而提高了液位测量精度。图4参2(李士范)
基金supported in part by National Natural Science Funds for Creative Research Groups of China under Grant No. 61421061Huawei Innovation Research ProgramOpen Research Fund in Xi’an Jiaotong University under Grant No. sklms2015015
文摘One key advantage of 4G OFDM system is the relatively simple receiver implementation due to the orthogonal resource allocation.However,from sum-capacity and spectral efficiency points of view,orthogonal systems are never the achieving schemes.With the rapid development of mobile communication systems,a novel concept of non-orthogonal transmission for 5G mobile communications has attracted researches all around the world.In this trend,many new multiple access schemes and waveform modulation technologies were proposed.In this paper,some promising ones of them were discussed which include Non-orthogonal Multiple Access(NOMA),Sparse Code Multiple Access(SCMA),Multi-user Shared Access(MUSA),Pattern Division Multiple Access(PDMA)and some main new waveforms including Filter-bank based Multicarrier(FBMC),Universal Filtered Multi-Carrier(UFMC),Generalized Frequency Division Multiplexing(GFDM).By analyzing and comparing features of these technologies,a research direction of guiding on future 5G multiple access and waveform are given.
基金Supported by the National High Technology Research and Development Programme of China ( No. 2006AA040302 2007AA041201 +1 种基金 2007AA041301 )the National Creative Research Groups Science Foundation of China (No. 60721062)
文摘Many efforts have been made to develop time division multiple access （TDMA） slots allocation in a multi-hop converge-cast wireless sensor network （WSN）, however, most of them either use complex algorithm or concern frames only without simultaneous transmission in a single slot. In this paper, we present a timeslot assignment scheme for cluster-tree-based TDMA WSN, co：＇ering three frequently used working modes in practical applications. The shortest frame formed can guarantee real-time conununication and is also facilitated for message and slot integration, since timeslots allocated to a single node are continuous. During allocation processes, the algorithms are distributed and light-weighted. The experiment resulted from a WSN prototype system shows that our scheme can achieve a good reliability.
基金Project supported by the Second Stage of Brain Korea 21 ProjectsProject(10035236)supported by the IT_R&D Program of MKE/KEIT,Korea
文摘Though the WiMedia supports higher data rates than other WPAN technologies,a WiMedia device cannot reach other devices that are separated from it by more than 10 m,which is the typical limited transmission range of the WiMedia protocol.In this work,we propose a multi-hop QoS routing protocol to enable WiMedia devices to transmit real-time data to devices that are located out of the transmission range.The proposed routing protocol is a hybrid algorithm,which mixes the table-driven and on-demand routing algorithms,searching one or more routes according to the number of hops to a destination device.WiMedia MAC is potentially capable of learning the existence of neighbor devices by using a beacon frame.By utilizing the neighbors' information,all devices can create routing entries for devices within 2-hops periodically.For devices beyond the 2-hop range,the newly designed on-demand routing algorithm is applied to multi-hop routing.If a routing entry for a destination device is not listed in the routing table,the source device sends a request packet to 2-hop range devices which could be found in the routing table.Since every device maintains routing entries for 2-hop range devices in the routing table,the request packet is replied in advance before its arrival at the destination device.Also,to decide the optimal route for a destination device,the number of medium access slots(MASs),received signal strength indicator(RSSI)and hop count are utilized to establish a QoS-enabled routing table.We perform ns-2 simulation to investigate the performance of the proposed routing protocol with AODV and DSDV.The simulation results show that the proposed protocol has better throughput and lower overhead than other protocols.
基金Natural Science Foundation of Fujian Province(A992001)
文摘The time-resolved photoluminescence and steady photoluminescence (TRPL and PL) spectra on self-assembled InAs/GaAs quantum dots (QDs) are investigated. By depositing GaAs/InAs short period superlattices (SLs), 1.48μm emission is obtained at room temperature. Temperature dependent PL measurements show that the PL intensity of the emission is very steady. It decays only to half as the temperature increases from 15K to room temperature, while at the same time, the intensity of the other emission decreases by a factor of 5 orders of magnitude. These two emissions are attributed to large-size QDs and short period superlattices (SLs), respectively. Large-size QDs are easier to capture and confine carriers, which benefits the lifetime of PL, and therefore makes the emission intensity insensitive to the temperature.
基金Supported by the Shanghai Municipal Education Commission Foundation under Grant No. 06FZ039.
文摘This paper investigates the vibration characteristics of diesel engine cylinder heads by means of the time series method. With the concept of "Assumed System",the vibration transfer function of real cylinder head structures is established using the autoregressive-moving average models(ARMA models) of cylinder head surface vibration signals. Then this transfer function is successfully used to reconstruct the gas pressure trace inside the cylinder from measured cylinder head vibration signals. This offers an effective means for diesel engine cylinder pressure detection and condition monitoring.
基金Projects(11164007,61275174)supported by the National Natural Science Foundation of ChinaProject(20100162110068)supported by the Doctoral Program of Higher Education of China+1 种基金Project(20132BAB212007)supported by the Natural Science Foundation of Jiangxi Province,ChinaProject(GJJ11107)supported by Scientific Foundation of Jiangxi Education Department,China
文摘Metallic ring-shaped nanotube arrays are proposed and its optical transmission properties are studied by using finite-difference time-domain （FDTD） method. Compared with the transmission spectra of conventional circular nanotube arrays, two photonic band gaps are emerged in the transmission spectra offing-shaped nanotube arrays, the two band gaps and transmission spectra are adjusted by the length, inner radius, intertube spacing and the dielectric constants of the core and embedding medium, and magnitude modification, redshift and blueshift of the resonance modes are observed. A metallic ring-shaped nanotube arrays for subwavelength band-stop filter in the range of visible light can be achieved. To understand its physical origin, field-interference mechanism was suggested by the field distributions. The proposed nanostructures and results may have great potential applications in subwavelength near-field optics.
