With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media a...With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media access control (MAC) protocols, which allow multiple users to share the common medium fairly and efficiently, are essential for the performance of UASNs. However, the design of MAC protocols is confronted with the challenges of spatial unfairness, data eruption, and low energy efficiency. In this paper, we propose a novel data concurrent transmission (DCT) MAC protocol, which is able to exploit long propagation delay and conduct concurrent transmission. Specifically, we present the theoretical performance analysis of the proposed MAC protocol in detail and give an analytical solution of the success concurrent transmission probability between nodes. In addition, simulation results are provided to demonstrate that our proposed protocol is appropriate for UASNs and can significantly improve the performance in terms of network throughput and energy consumption. Finally, we give some typical future applications of UASNs and discuss the demands on MAC protocol design.展开更多
OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Trans...OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.展开更多
A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified sce...A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified scenarios with one to two hops or multihop scenarios with a custody mechanism of the Bundle Protocol(BP).However,the research results are not applicable to communications in Complex Deep Space Networks(CDSNs)without the custody mechanism of BP that are more suitable for deep space communications with LTP.In this paper,we propose a model of file delivery time for LTP in CDSNs.Based on the model,we propose a Parameter Optimization Design Algorithm for LTP(LTP-PODA)of configuring reasonable parameters for LTP.The results show that the accuracy of the proposed model is at least 6.47%higher than that of the previously established models based on simple scenarios,and the proposed model is more suitable for CDSNs.Moreover,the LTP parameters are optimized by the LTP-PODA algorithm to obtain an optimization plan.Configuring the optimization plan for LTP improves the protocol transmission performance by at least 18.77%compared with configuring the other parameter configuration plans.展开更多
In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the s...In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.展开更多
Most of the internet users connect through wireless networks. Majorpart of internet traffic is carried by Transmission Control Protocol (TCP). It hassome design constraints while operated across wireless networks. TCP...Most of the internet users connect through wireless networks. Majorpart of internet traffic is carried by Transmission Control Protocol (TCP). It hassome design constraints while operated across wireless networks. TCP is the traditional predominant protocol designed for wired networks. To control congestionin the network, TCP used acknowledgment to delivery of packets by the end host.In wired network, packet loss signals congestion in the network. But rather inwireless networks, loss is mainly because of the wireless characteristics such asfading, signal strength etc. When a packet travels across wired and wireless networks, TCP congestion control theory faces problem during handshake betweenthem. This paper focuses on finding this misinterpretation of the losses using crosslayer approach. This paper focuses on increasing bandwidth usage by improvingTCP throughput in wireless environments using cross layer approach and hencenamed the proposed system as CRLTCP. TCP misinterprets wireless loss as congestion loss and unnecessarily reduces congestion window size. Using the signalstrength and frame error rate, the type of loss is identified and accordingly theresponse of TCP is modified. The results show that there is a significant improvement in the throughput of proposed TCP upon which bandwidth usage isincreased.展开更多
In the wireless sensor networks, the wireless resources are very limited. In the design of the MAC protocols, how to make full use of the limited channel resources to complete more data communications must be consider...In the wireless sensor networks, the wireless resources are very limited. In the design of the MAC protocols, how to make full use of the limited channel resources to complete more data communications must be considered as much as possible. In this paper, in view of the shortcomings of the OPC method on decisions of parallel communications, an opportunistic concurrency transmis- sion MAC protocol based on geographic location information (OPCLI-MAC) is proposed, an improved local parallel mapping table and a parallel control algo- rithm are proposed. The node location information is added to the mapping table. The parallel control algorithm is carried out using the distance value to deal with the problems of the parallel transmission link' s two terminals. Experiments show that the OPCLI-MAC protocol reduces the interference of the newly launched parallel transmission link to the ongoing data communications, optimizes the parallel transmission communication decision, improves the probability of the parallel transmissions, and improves the channel utilization.展开更多
The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of t...The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.展开更多
Nowadays, there is a growing emphasis on Inter-basin water transfer projects as costly activities with ambiguous effects on environment, society and economy. Since the concept of climate change was in its embryonic ph...Nowadays, there is a growing emphasis on Inter-basin water transfer projects as costly activities with ambiguous effects on environment, society and economy. Since the concept of climate change was in its embryonic phase before 1990’s, the majority of these projects planned before that period have not considered the effect of long term variation of water resources. In all of these numerous operational and under-construction projects, an intelligent selection of the best water transmission protocol, can help the governments to optimize their expenditures on these projects ,and also can help water resources managers to face climate change effects wisely. In this paper as a case study, Dez to Qomrood inter-basin water transfer project is considered to evaluate the efficiency of three different protocols in long term. The effect of climate change has been forecasted via a wide range of GCMs (Global Circulation Model) in order to calculate the change of flow in the basin's area with different climate scenarios. After these calculation, a water allocation model has been used to evaluate which of these three water transmission protocols (Proportional Allocation (PA), Fix Upstream allocation (FU), and Fix Downstream allocation (FD)) is the most efficient logic switch economically in a framework including both upstream and downstream stakeholders. As the final result, it can be inferred that Fix Downstream allocation (FD) protocol can supply more population especially with urban water for a fix expense and also is the most adapted protocol with future global change, at least in the first round of sustainability assessment.展开更多
The symbol-error-rate(SER) and power allocation for hybrid cooperative(HC) transmission system are investigated.Closed-form SER expression is derived by using the moment generating function(MGF)-based approach.H...The symbol-error-rate(SER) and power allocation for hybrid cooperative(HC) transmission system are investigated.Closed-form SER expression is derived by using the moment generating function(MGF)-based approach.However,the resultant SER contains an MGF of the harmonic mean of two independent random variables(RVs),which is not tractable in SER analysis.We present a simple MGF expression of the harmonic mean of two independent RVs which avoids the hypergeometric functions used commonly in previous studies.Using the simple MGF,closed-form SER for HC system with M-ary phase shift keying(M-PSK) signals is provided.Further,an approximation as well as an upper bound of the SER is presented.It is shown that the SER approximation is asymptotically tight.Based on the tight SER approximation,the power allocation of the HC system is investigated.It is shown that the optimal power allocation does not depend on the fading parameters of the source-destination(SD) channel and it only depends on the source-relay(SR) and relay-destination(RD) channels.Moreover,the performance gain of the power allocation depends on the ratio of the channel quality between RD and SR.With the increase of this ratio,more performance gain can be acquired.展开更多
To guarantee control system's performance and shorten the development cycle during the development process of hydraulic automatic transmission, a calibration system on CAN for high-pow- er AT ECU is designed based on...To guarantee control system's performance and shorten the development cycle during the development process of hydraulic automatic transmission, a calibration system on CAN for high-pow- er AT ECU is designed based on XCP. In this system, it is possible that the master dynamically searching the slaves available on bus and data synchronization between master and slave is also achieved. Real-time measurement and on-line calibration can be executed during the running process of transmission control unit, so the calibration result is displayed in time. Calibration by true value and physical value are both available. Experimental results showed that this system operated stably and reliably and had strong timeout handling ability.展开更多
An intelligent detecting system based on wireless transmission is designed. Its hardware includes the card reading module, the wireless digital transmission module, the LCD module, the random password keyboard module ...An intelligent detecting system based on wireless transmission is designed. Its hardware includes the card reading module, the wireless digital transmission module, the LCD module, the random password keyboard module and a 16×16 lattice word database based on e-Flash MM36SB020. Its software is a communication protocol between the central control computer and the entrance management base station. To resolve the conflicting problems occurred during the data transmission, a method of delaying time at random is proposed.展开更多
Distributed speech recognition (DSR) applications have certain QoS (Quality of service) requirements in terms of latency, packet loss rate, etc. To deliver quality guaranteed DSR application over wirelined or wireless...Distributed speech recognition (DSR) applications have certain QoS (Quality of service) requirements in terms of latency, packet loss rate, etc. To deliver quality guaranteed DSR application over wirelined or wireless links, some QoS mechanisms should be provided. We put forward a RTP/RSVP transmission scheme with DSR-specific payload and QoS parameters by modifying the present WAP protocol stack. The simulation result shows that this scheme will provide adequate network bandwidth to keep the real-time transport of DSR data over either wirelined or wireless channels.展开更多
Two significant issues in Internet-based networked control systems ( INCSs), transport performance of different protocols and security breach from Internet side, are investigated. First, for improving the performanc...Two significant issues in Internet-based networked control systems ( INCSs), transport performance of different protocols and security breach from Internet side, are investigated. First, for improving the performance of data transmission, user datagram protocol (UDP) is adopted as the main stand for controllers and plants using INCSs. Second, a dual-channel secure transmission scheme (DCSTS)based on data transmission characteristics of INCSs is proposed, in which a raw UDP channel and a secure TCP (transmission control protocol) connection making use of SSL/TLS (secure sockets layerransport layer security) are included. Further, a networked control protocol (NCP) at application layer for supporting DCSTS between the controllers and plants in INCSs is designed, and it also aims at providing a universal communication mechanism for interoperability of devices among the networked control laboratories in Beijing Institute of Technology of China, Central South University of China and Tokyo University of Technology of Japan. By means of a networked single-degree-of-free- dom robot arm, an INCS under the new protocol and security environment is created. Compared with systems such as IPSec or SSL/TLS, which may cause more than 91% network throughput deduction, the new DCSTS protocol may yield results ten times better, being just 5.67%.展开更多
There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great ...There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks. This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.展开更多
The goal of this paper is to propose a fast and secure multi-stage image compression-decompression system by using a wireless network between two Personal Computers (PCs). In this paper, the Principal Component Analys...The goal of this paper is to propose a fast and secure multi-stage image compression-decompression system by using a wireless network between two Personal Computers (PCs). In this paper, the Principal Component Analysis (PCA) technique is used for multi-stage image compression and Inverse Principal Component Analysis (IPCA) for multi-stage image decompression. The first step of the proposed system is to select the input image, the second step is to perform PCA up to 9 times on the input image, this compression, and after multi-stage compression process then the third step begins by transforming across wireless Ad hoc Network (WANET) to the second computing device, forth step start with multi-stage decompression process up 9 times. The proposed system for different images is transferred over the wireless network using Transmission Control Protocol/Internet Protocol (TCP/IP), which is programmed using the network role property of the MATLAB program. The proposed system implements 25 different images correctly (100%). The main contribution of this paper is that we are dealing with the black image at the end of the compressed process ad start with a black image at the start of the decompressed process of this proposed system. In this work, the compressed and uncompressed images are compared with each other in their size and transmission time. This system can be very useful in networks because they provide a high level of protection to the transmitted data from hackers because they cannot guess how much the image has been compressed or what kind of information the image represents.展开更多
Because of its portability,the non-cable seismograph has become the future development trend of geophysical instruments.A new wireless data transmission device of 433 M module was proposed;a wireless network was built...Because of its portability,the non-cable seismograph has become the future development trend of geophysical instruments.A new wireless data transmission device of 433 M module was proposed;a wireless network was built using the EL1663B_PA module of the SI4463 core,and through the SPI interface to modify the internal parameters.Data transmission used dual antenna mode,the main station as the center of the wireless network coverage up to 550 m or more.The wireless time synchronization system was designed to realize the wireless connection communication between the shallow seismograph and the sensor of each observation point.This program aimed to eliminate the necessary connecting cable and batteries between the conventional shallow seismograph and the detector,greatly reducing the weight of the equipment,and making the shallow seismograph truly low cost,lightweight,flexible and easy to operate and so on.展开更多
在多应用的复杂恶劣环境,通常数据传输的耗能对电池供电的传感云网络中无线传感器工作寿命的影响一直是研究热点问题。因此,针对传感云网络多源数据提出一种低时延多径协同传输方法。构建包含基站、中继节点和目的节点的两跳有损网络,...在多应用的复杂恶劣环境,通常数据传输的耗能对电池供电的传感云网络中无线传感器工作寿命的影响一直是研究热点问题。因此,针对传感云网络多源数据提出一种低时延多径协同传输方法。构建包含基站、中继节点和目的节点的两跳有损网络,根据选取原则确定合适的目的节点和中继节点。然后,基于随机线性网络编码(Random Linear Network Coding,RLNC)的用户数据报协议(User Datagram Protocol,UDP)实现多源数据的低时延传输。最后,在此基础上,选择一种低能耗的最佳协同传输策略,在保证无线传感云网络吞吐量最大化的前提下,完成多源数据高效的协同传输。结果表明,所提方法数据递交率不低于99%,数据传输能耗最高为51 k Wh,数据递交时延为15.5 ms,丢包率为0,具有较强的多源数据传输性能。展开更多
This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the control...This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the controller is implemented via a constrained communication channel.The quantised output of the system is transmitted to the remote controller through a communication channel subject to a transmission delay.For the purpose of alleviating possible data collision,the well-known RR communication protocol is deployed to schedule the data transmissions.On the other hand,the uniform quantisation effects of the network are characterised by a round function(i.e.the nearest integer function).The purpose of the addressed problem is to design an observer-based controller for the networked nonlinear systems such that,in the presence of RR protocol and uniform quantisation effects,the closed-loop system is ultimately bounded.The controller is designed based on mean square stability analysis and Lyapunov-like method.A set of sufficient conditions for the ultimate boundedness of the closed-loop system are established and,on the basis of which,the desired controller gains are obtained by solving a set of linear matrix inequalities.The effectiveness of the proposed method is verified by numerical examples.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 62171405in part by the National Science Fund for Distinguished Young Scholars under Grant 62225114
摘要With the increasing demand for marine exploration, underwater acoustic sensor networks (UASNs) are prone to have the characteristics of large-scale, long term monitoring, and high data traffic load. Underwater media access control (MAC) protocols, which allow multiple users to share the common medium fairly and efficiently, are essential for the performance of UASNs. However, the design of MAC protocols is confronted with the challenges of spatial unfairness, data eruption, and low energy efficiency. In this paper, we propose a novel data concurrent transmission (DCT) MAC protocol, which is able to exploit long propagation delay and conduct concurrent transmission. Specifically, we present the theoretical performance analysis of the proposed MAC protocol in detail and give an analytical solution of the success concurrent transmission probability between nodes. In addition, simulation results are provided to demonstrate that our proposed protocol is appropriate for UASNs and can significantly improve the performance in terms of network throughput and energy consumption. Finally, we give some typical future applications of UASNs and discuss the demands on MAC protocol design.
基金High-Tech Research and DevelopmentProgram of China (No. 2003AA123310)
摘要OAM (Operations, Administration and Maintenance) system is a very impo rtant component of 3G cellular network. In order to acquire overall managemen t, fast response and steady operation, an SCTP (Stream Control Transmission Prot ocol) based OAM, i.e., SOAM system was proposed. SOAM implements new characters of SCTP such as multi-stream, enforced SACK and heartbeat mechanism on its tran sport layer. These characters help SOAM decrease the message transmission delay and accelerate the link failure detection. Besides, a new component named SOAM agent was introduced to improve the operation efficiency of SOAM. The experim ental results prove the proposed SOAM system achieves better performance on sign aling transmission compared with conventional TCP based OAM system.
基金supported by the Strategic Leading Project of the Chinese Academy of Sciences(No.XDA15014603).
摘要A reasonable parameter configuration helps improve the data transmission performance of the Licklider Transmission Protocol(LTP).Previous research has focused mainly on parameter optimization for LTP in simplified scenarios with one to two hops or multihop scenarios with a custody mechanism of the Bundle Protocol(BP).However,the research results are not applicable to communications in Complex Deep Space Networks(CDSNs)without the custody mechanism of BP that are more suitable for deep space communications with LTP.In this paper,we propose a model of file delivery time for LTP in CDSNs.Based on the model,we propose a Parameter Optimization Design Algorithm for LTP(LTP-PODA)of configuring reasonable parameters for LTP.The results show that the accuracy of the proposed model is at least 6.47%higher than that of the previously established models based on simple scenarios,and the proposed model is more suitable for CDSNs.Moreover,the LTP parameters are optimized by the LTP-PODA algorithm to obtain an optimization plan.Configuring the optimization plan for LTP improves the protocol transmission performance by at least 18.77%compared with configuring the other parameter configuration plans.
基金Supported by the National Natural Science Foun-dation of China (60572049) the Natural Science Foundation ofHubei Province of China (2005ABA264)
摘要In order to minimize the energy consumption in the discovery of the routing path, this paper introduces a novel concept of effective transmission (ET) that ensures each forwarding node is not only farther from the source node, but also nearer to the destination node with respect to its sender, An energ-aware routing protocol based on ET is proposed. It enables the energy consumption for each hop to be the least for the transmission. The simulation results show the routing protocol is effective in the performance of energy consumption comparing with some other routing protocols.
摘要Most of the internet users connect through wireless networks. Majorpart of internet traffic is carried by Transmission Control Protocol (TCP). It hassome design constraints while operated across wireless networks. TCP is the traditional predominant protocol designed for wired networks. To control congestionin the network, TCP used acknowledgment to delivery of packets by the end host.In wired network, packet loss signals congestion in the network. But rather inwireless networks, loss is mainly because of the wireless characteristics such asfading, signal strength etc. When a packet travels across wired and wireless networks, TCP congestion control theory faces problem during handshake betweenthem. This paper focuses on finding this misinterpretation of the losses using crosslayer approach. This paper focuses on increasing bandwidth usage by improvingTCP throughput in wireless environments using cross layer approach and hencenamed the proposed system as CRLTCP. TCP misinterprets wireless loss as congestion loss and unnecessarily reduces congestion window size. Using the signalstrength and frame error rate, the type of loss is identified and accordingly theresponse of TCP is modified. The results show that there is a significant improvement in the throughput of proposed TCP upon which bandwidth usage isincreased.
摘要In the wireless sensor networks, the wireless resources are very limited. In the design of the MAC protocols, how to make full use of the limited channel resources to complete more data communications must be considered as much as possible. In this paper, in view of the shortcomings of the OPC method on decisions of parallel communications, an opportunistic concurrency transmis- sion MAC protocol based on geographic location information (OPCLI-MAC) is proposed, an improved local parallel mapping table and a parallel control algo- rithm are proposed. The node location information is added to the mapping table. The parallel control algorithm is carried out using the distance value to deal with the problems of the parallel transmission link' s two terminals. Experiments show that the OPCLI-MAC protocol reduces the interference of the newly launched parallel transmission link to the ongoing data communications, optimizes the parallel transmission communication decision, improves the probability of the parallel transmissions, and improves the channel utilization.
摘要The necessary background as well as the details of simulation was presented to simulate and evaluate the performance of the ad hoc on-demand distance vector routing protocol in mobile ad hoc network with the help of the network simulator NS2 using the common transmission range to deliver the data packets at the destination node. The number of participating nodes played an important role to predict the conditions for the best performance of the protocol with respect to throughput, delay, packet delivery ratio, drop packets, consumed and residual energy of the network. Further, the efforts can be put to control the transmission range dynamically and overheads for reducing the energy consumption in the network and improving its lifetime of the nodes and the lifespan of the network.
摘要Nowadays, there is a growing emphasis on Inter-basin water transfer projects as costly activities with ambiguous effects on environment, society and economy. Since the concept of climate change was in its embryonic phase before 1990’s, the majority of these projects planned before that period have not considered the effect of long term variation of water resources. In all of these numerous operational and under-construction projects, an intelligent selection of the best water transmission protocol, can help the governments to optimize their expenditures on these projects ,and also can help water resources managers to face climate change effects wisely. In this paper as a case study, Dez to Qomrood inter-basin water transfer project is considered to evaluate the efficiency of three different protocols in long term. The effect of climate change has been forecasted via a wide range of GCMs (Global Circulation Model) in order to calculate the change of flow in the basin's area with different climate scenarios. After these calculation, a water allocation model has been used to evaluate which of these three water transmission protocols (Proportional Allocation (PA), Fix Upstream allocation (FU), and Fix Downstream allocation (FD)) is the most efficient logic switch economically in a framework including both upstream and downstream stakeholders. As the final result, it can be inferred that Fix Downstream allocation (FD) protocol can supply more population especially with urban water for a fix expense and also is the most adapted protocol with future global change, at least in the first round of sustainability assessment.
基金supported by the National Basic Research Program of China (973 Program) (2010CB731803)the National Science Foundation for Innovative Research Groups of China (60921001)
摘要The symbol-error-rate(SER) and power allocation for hybrid cooperative(HC) transmission system are investigated.Closed-form SER expression is derived by using the moment generating function(MGF)-based approach.However,the resultant SER contains an MGF of the harmonic mean of two independent random variables(RVs),which is not tractable in SER analysis.We present a simple MGF expression of the harmonic mean of two independent RVs which avoids the hypergeometric functions used commonly in previous studies.Using the simple MGF,closed-form SER for HC system with M-ary phase shift keying(M-PSK) signals is provided.Further,an approximation as well as an upper bound of the SER is presented.It is shown that the SER approximation is asymptotically tight.Based on the tight SER approximation,the power allocation of the HC system is investigated.It is shown that the optimal power allocation does not depend on the fading parameters of the source-destination(SD) channel and it only depends on the source-relay(SR) and relay-destination(RD) channels.Moreover,the performance gain of the power allocation depends on the ratio of the channel quality between RD and SR.With the increase of this ratio,more performance gain can be acquired.
基金Supported by the National High Technology Research and Development Program of China("863" Program)(2012AA111713)
摘要To guarantee control system's performance and shorten the development cycle during the development process of hydraulic automatic transmission, a calibration system on CAN for high-pow- er AT ECU is designed based on XCP. In this system, it is possible that the master dynamically searching the slaves available on bus and data synchronization between master and slave is also achieved. Real-time measurement and on-line calibration can be executed during the running process of transmission control unit, so the calibration result is displayed in time. Calibration by true value and physical value are both available. Experimental results showed that this system operated stably and reliably and had strong timeout handling ability.
摘要An intelligent detecting system based on wireless transmission is designed. Its hardware includes the card reading module, the wireless digital transmission module, the LCD module, the random password keyboard module and a 16×16 lattice word database based on e-Flash MM36SB020. Its software is a communication protocol between the central control computer and the entrance management base station. To resolve the conflicting problems occurred during the data transmission, a method of delaying time at random is proposed.
摘要Distributed speech recognition (DSR) applications have certain QoS (Quality of service) requirements in terms of latency, packet loss rate, etc. To deliver quality guaranteed DSR application over wirelined or wireless links, some QoS mechanisms should be provided. We put forward a RTP/RSVP transmission scheme with DSR-specific payload and QoS parameters by modifying the present WAP protocol stack. The simulation result shows that this scheme will provide adequate network bandwidth to keep the real-time transport of DSR data over either wirelined or wireless channels.
摘要Two significant issues in Internet-based networked control systems ( INCSs), transport performance of different protocols and security breach from Internet side, are investigated. First, for improving the performance of data transmission, user datagram protocol (UDP) is adopted as the main stand for controllers and plants using INCSs. Second, a dual-channel secure transmission scheme (DCSTS)based on data transmission characteristics of INCSs is proposed, in which a raw UDP channel and a secure TCP (transmission control protocol) connection making use of SSL/TLS (secure sockets layerransport layer security) are included. Further, a networked control protocol (NCP) at application layer for supporting DCSTS between the controllers and plants in INCSs is designed, and it also aims at providing a universal communication mechanism for interoperability of devices among the networked control laboratories in Beijing Institute of Technology of China, Central South University of China and Tokyo University of Technology of Japan. By means of a networked single-degree-of-free- dom robot arm, an INCS under the new protocol and security environment is created. Compared with systems such as IPSec or SSL/TLS, which may cause more than 91% network throughput deduction, the new DCSTS protocol may yield results ten times better, being just 5.67%.
摘要There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks. This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.
摘要The goal of this paper is to propose a fast and secure multi-stage image compression-decompression system by using a wireless network between two Personal Computers (PCs). In this paper, the Principal Component Analysis (PCA) technique is used for multi-stage image compression and Inverse Principal Component Analysis (IPCA) for multi-stage image decompression. The first step of the proposed system is to select the input image, the second step is to perform PCA up to 9 times on the input image, this compression, and after multi-stage compression process then the third step begins by transforming across wireless Ad hoc Network (WANET) to the second computing device, forth step start with multi-stage decompression process up 9 times. The proposed system for different images is transferred over the wireless network using Transmission Control Protocol/Internet Protocol (TCP/IP), which is programmed using the network role property of the MATLAB program. The proposed system implements 25 different images correctly (100%). The main contribution of this paper is that we are dealing with the black image at the end of the compressed process ad start with a black image at the start of the decompressed process of this proposed system. In this work, the compressed and uncompressed images are compared with each other in their size and transmission time. This system can be very useful in networks because they provide a high level of protection to the transmitted data from hackers because they cannot guess how much the image has been compressed or what kind of information the image represents.
基金National Natural Science Foundation of China(grant number 41774116).
摘要Because of its portability,the non-cable seismograph has become the future development trend of geophysical instruments.A new wireless data transmission device of 433 M module was proposed;a wireless network was built using the EL1663B_PA module of the SI4463 core,and through the SPI interface to modify the internal parameters.Data transmission used dual antenna mode,the main station as the center of the wireless network coverage up to 550 m or more.The wireless time synchronization system was designed to realize the wireless connection communication between the shallow seismograph and the sensor of each observation point.This program aimed to eliminate the necessary connecting cable and batteries between the conventional shallow seismograph and the detector,greatly reducing the weight of the equipment,and making the shallow seismograph truly low cost,lightweight,flexible and easy to operate and so on.
摘要在多应用的复杂恶劣环境,通常数据传输的耗能对电池供电的传感云网络中无线传感器工作寿命的影响一直是研究热点问题。因此,针对传感云网络多源数据提出一种低时延多径协同传输方法。构建包含基站、中继节点和目的节点的两跳有损网络,根据选取原则确定合适的目的节点和中继节点。然后,基于随机线性网络编码(Random Linear Network Coding,RLNC)的用户数据报协议(User Datagram Protocol,UDP)实现多源数据的低时延传输。最后,在此基础上,选择一种低能耗的最佳协同传输策略,在保证无线传感云网络吞吐量最大化的前提下,完成多源数据高效的协同传输。结果表明,所提方法数据递交率不低于99%,数据传输能耗最高为51 k Wh,数据递交时延为15.5 ms,丢包率为0,具有较强的多源数据传输性能。
基金supported in part by the National Natural Science Foundation of China under Grants 62173079 and U1808205the Science and Technology Program of Gansu Province under Grant 21ZD4GA028.
摘要This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the controller is implemented via a constrained communication channel.The quantised output of the system is transmitted to the remote controller through a communication channel subject to a transmission delay.For the purpose of alleviating possible data collision,the well-known RR communication protocol is deployed to schedule the data transmissions.On the other hand,the uniform quantisation effects of the network are characterised by a round function(i.e.the nearest integer function).The purpose of the addressed problem is to design an observer-based controller for the networked nonlinear systems such that,in the presence of RR protocol and uniform quantisation effects,the closed-loop system is ultimately bounded.The controller is designed based on mean square stability analysis and Lyapunov-like method.A set of sufficient conditions for the ultimate boundedness of the closed-loop system are established and,on the basis of which,the desired controller gains are obtained by solving a set of linear matrix inequalities.The effectiveness of the proposed method is verified by numerical examples.