The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the ge...The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.展开更多
Several software network models are constructed based on the relationships between classes in the object-oriented software systems.Then,a variety of well-known open source software applications are statistically analy...Several software network models are constructed based on the relationships between classes in the object-oriented software systems.Then,a variety of well-known open source software applications are statistically analyzed by using these models.The results show that: (1) Dependency network does play a key role in software architecture;(2) The exponents of in-degree and total-degree distribution functions of different networks differ slightly,while the exponent of out-degree varies obviously;(3) Weak-coupling relationships have greater impact on software architecture than strong-coupling relationships.Finally,a theoretically analysis on these statistical phenomena is proposed from the perspectives of software develop technology,develop process and developer’s habits,respectively.展开更多
This paper presents a new semi-fragile watermarking algorithm for image authentication which extracts image features from the low frequency domain to generate two watermarks: one for classifying of the intentional con...This paper presents a new semi-fragile watermarking algorithm for image authentication which extracts image features from the low frequency domain to generate two watermarks: one for classifying of the intentional content modification and the other for indicating the modified location. The algorithm provides an effective mechanism for image authentication. The watermark generation and watermark embedment are disposed in the image itself, and the received image authentication needs no information about the original image or watermark. The algorithm increases watermark security and prevents forged watermark. Experimental results show that the algorithm can identify intentional content modification and incidental tampering, and also indicate the location where a modification takes place.展开更多
Connectivity is the premise and foundation of networking and routing.For the probabilistic flight path of military aircraft resulting in the difficulty of Aeronautical Ad hoc NETwork(AANET) research,an estimation meth...Connectivity is the premise and foundation of networking and routing.For the probabilistic flight path of military aircraft resulting in the difficulty of Aeronautical Ad hoc NETwork(AANET) research,an estimation method of connectivity probability is proposed.The method takes airspace as the research object,starts with actual flight characteristics,and applies conclusions of random waypoint mobility model.Building a connectivity model by establishing Airspace Unit Circle(AUC) from the perspective of circle-circle coverage,the method obtains a theory of airspace network connectivity.Experiment demonstrates its correctness.Finally,according to the actual condition simulation,relationship between the number of aircraft,communication radius,and the flight area under connectivity probabilities is achieved,results provide reference for creating a network that under certain aerial combat condition.展开更多
Mobile multicast is important for the emerging applications such as mobile video or audio conference and mobile IPTV.Some mobile multicast schemes have been proposed in the past few years, but most of them study the r...Mobile multicast is important for the emerging applications such as mobile video or audio conference and mobile IPTV.Some mobile multicast schemes have been proposed in the past few years, but most of them study the reconstruc-tion of multicast delivery tree, and few consider the group membership management for mobile sub-scribers.In this paper, we propose a new mobile multicast method based on the Two-Hop Multicast Listener Discovery(THMLD) protocol which pro-vides the mobile multicast membership manage-ment function by forwarding the traditional MLD messages to its neighboring subnets.To evaluate its performance, we analyze the THMLD and set up the simulation platform to compare it with the several traditional mobile multicast methods.The results show that THMLD can reduce the multicast join time, and the THMLD-based mobile multicast method can reduce the multicast join delay at a cost of increasing additional multicast maintenance cost.展开更多
For the published block cipher algorithm, two kinds of round functions have been researched.Block ciphers in network environments are taking more risks than ever before because of their initialization key's distri...For the published block cipher algorithm, two kinds of round functions have been researched.Block ciphers in network environments are taking more risks than ever before because of their initialization key's distribution in the internet.The security of block cipher algorithm is affected by linear bias and nonlinear bias which are restricted by confusion layer and diffusion layer.This article takes an approach on how block cipher's two round structures are initially transformed when they fuse into LFSR.The SP structure can be considered two F functions in one Feistel round function which combines both right and left of origin data transformation.Furthermore, the round number linear function and nonlinear function of Feistel and SP structure are compared.The merit of SP structure is that it can fuse in LFSR as a nonlinear filter without memory.展开更多
New challenges are introduced when people try to build a general-purpose mobile agent middleware in Grid envi- ronment. In this paper, an instance-oriented security mechanism is proposed to deal with possible security...New challenges are introduced when people try to build a general-purpose mobile agent middleware in Grid envi- ronment. In this paper, an instance-oriented security mechanism is proposed to deal with possible security threats in such mobile agent systems. The current security support in Grid Security Infrastructure (GSI) requires the users to delegate their privileges to certain hosts. This host-oriented solution is insecure and inflexible towards mobile agent applications because it cannot prevent delegation abuse and control well the diffusion of damage. Our proposed solution introduces security instance, which is an en- capsulation of one set of authorizations and their validity specifications with respect to the agent’s specific code segments, or even the states and requests. Applications can establish and configure their security framework flexibly on the same platform, through defining instances and operations according to their own logic. Mechanisms are provided to allow users delegating their identity to these instances instead of certain hosts. By adopting this instance-oriented security mechanism, a Grid-based general-purpose MA middleware, Everest, is developed to enhance Globus Toolkit’s security support for mobile agent applications.展开更多
BitTorrent is a very popular Peer-to-Peer file sharing system, which adopts a set of incentive mechanisms to encourage contribution and prevent free-riding. However, we find that BitTorrent’s incentive mechanism can ...BitTorrent is a very popular Peer-to-Peer file sharing system, which adopts a set of incentive mechanisms to encourage contribution and prevent free-riding. However, we find that BitTorrent’s incentive mechanism can prevent free-riding effectively in a system with a relatively low number of seeds, but may fail in producing a disincentive for free-riding in a system with a high number of seeds. The reason is that BitTorrent does not provide effective mechanisms for seeds to guard against free-riding. Therefore, we propose a seed bandwidth allocation strategy for the BitTorrent system to reduce the effect of seeds on free-riding. Our target is that a downloader which provides more service to the system will be granted a higher benefit than downloaders which provide lower service when some downloaders ask for downloading file from a seed. Finally, simulation results are given, which validate the effectiveness of the proposed strategy.展开更多
A distributed QoS (quality of service) -aware source-specific multicast routing protocol—DQSSMR is proposed to increase the successful join ratio and lower the overhead of the control message in QoS required multicas...A distributed QoS (quality of service) -aware source-specific multicast routing protocol—DQSSMR is proposed to increase the successful join ratio and lower the overhead of the control message in QoS required multicast routing. By an improved searching strategy, the cost of message control is reduced and the successful join ratio is increased. The network load is balanced due to the distributed routing operation and the scalability is enhanced further because of the usage of SSM (source- specific multicast) service model in DQSSMR. The analysis results indicate that DQSSMR performs as expected.展开更多
In this paper,an Adaptive-Weighted Time-Dimensional and Space-Dimensional(AWTDSD) data aggregation algorithm for a clustered sensor network is proposed for prolonging the lifetime of the network as well as improving t...In this paper,an Adaptive-Weighted Time-Dimensional and Space-Dimensional(AWTDSD) data aggregation algorithm for a clustered sensor network is proposed for prolonging the lifetime of the network as well as improving the accuracy of the data gathered in the network.AWTDSD contains three phases:(1) the time-dimensional aggregation phase for eliminating the data redundancy;(2) the adaptive-weighted aggregation phase for further aggregating the data as well as improving the accuracy of the aggregated data; and(3) the space-dimensional aggregation phase for reducing the size and the amount of the data transmission to the base station.AWTDSD utilizes the correlations between the sensed data for reducing the data transmission and increasing the data accuracy as well.Experimental result shows that AWTDSD can not only save almost a half of the total energy consumption but also greatly increase the accuracy of the data monitored by the sensors in the clustered network.展开更多
To solve the problems of high memory occupation, low connectivity and poor resiliency against node capture, which existing in the random key pre-distribution techniques while applying to the large scale Wireless Senso...To solve the problems of high memory occupation, low connectivity and poor resiliency against node capture, which existing in the random key pre-distribution techniques while applying to the large scale Wireless Sensor Networks （WSNs）, an Identity-Based Key Agreement Scheme （IBKAS） is proposed based on identity-based encryption and Elliptic Curve Diffie-Hellman （ECDH）. IBKAS can resist man-in-the-middle attacks and node-capture attacks through encrypting the key agreement parameters using identity-based encryption. Theoretical analysis indicates that comparing to the random key pre-distribution techniques, IBKAS achieves significant improvement in key connectivity, communication overhead, memory occupation, and security strength, and also enables efficient secure rekcying and network expansion. Furthermore, we implement IBKAS for TinyOS-2.1.2 based on the MICA2 motes, and the experiment results demonstrate that IBKAS is feasible for infrequent key distribution and rekeying for large scale sensor networks.展开更多
The paper analyze and design and implement a remote control system based on network. A computer network remote control system mainly includes server, client and the control information. Server registration information...The paper analyze and design and implement a remote control system based on network. A computer network remote control system mainly includes server, client and the control information. Server registration information realize the user command; client provides network hardware, software and other system resources, the system response message and then feedback service instruction; control information transmission layer implementation using TCPflP protocol to control information including control of resources and control commands etc.. This paper adopts centralized network control system model, the structure of the network system realize unified observation, control, coordination, and control of high efficiency. The use of key technologies, such as Socket and COM to realize the goal of computer hardware resource control, software resource management and other functions.展开更多
The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology ...The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology innovation cooperation, and Ucinet characterization analysis software is used to compute characteristic values of simulation network such as power law index of network, average route length and accumulation coefficients. It is compared with the actual network, and the simulation results are analyzed to verify the rationality of the constructed evolution model.展开更多
Computer networks have to support an everincreasing array of applications,ranging from cloud computing in datacenters to Internet access for users.In order to meet the various demands,a large number of network devices...Computer networks have to support an everincreasing array of applications,ranging from cloud computing in datacenters to Internet access for users.In order to meet the various demands,a large number of network devices running different protocols are designed and deployed in networks.展开更多
文摘The theory and its method of machining parameter optimization for high-speed machining are studied. The machining data collected from workshops, labs and references are analyzed. An optimization method based on the genetic algorithm (GA) is investigated. Its calculation speed is faster than that of traditional optimization methods, and it is suitable for the machining parameter optimization in the automatic manufacturing system. Based on the theoretical studies, a system of machining parameter management and optimization is developed. The system can improve productivity of the high-speed machining centers.
基金The paper is supported by the National High Technology Research and Development Program of China （863 Program） （No.2009AA01Z439） and the National Natural Science Foundation of China （U0835001）
文摘Several software network models are constructed based on the relationships between classes in the object-oriented software systems.Then,a variety of well-known open source software applications are statistically analyzed by using these models.The results show that: (1) Dependency network does play a key role in software architecture;(2) The exponents of in-degree and total-degree distribution functions of different networks differ slightly,while the exponent of out-degree varies obviously;(3) Weak-coupling relationships have greater impact on software architecture than strong-coupling relationships.Finally,a theoretically analysis on these statistical phenomena is proposed from the perspectives of software develop technology,develop process and developer’s habits,respectively.
基金Supported by Hi-Tech R&D 863 Program of China (No. 20021111901010) and Scientific Research Fund of Hunan Provincial Education Department (No. 03A033)
文摘This paper presents a new semi-fragile watermarking algorithm for image authentication which extracts image features from the low frequency domain to generate two watermarks: one for classifying of the intentional content modification and the other for indicating the modified location. The algorithm provides an effective mechanism for image authentication. The watermark generation and watermark embedment are disposed in the image itself, and the received image authentication needs no information about the original image or watermark. The algorithm increases watermark security and prevents forged watermark. Experimental results show that the algorithm can identify intentional content modification and incidental tampering, and also indicate the location where a modification takes place.
文摘Connectivity is the premise and foundation of networking and routing.For the probabilistic flight path of military aircraft resulting in the difficulty of Aeronautical Ad hoc NETwork(AANET) research,an estimation method of connectivity probability is proposed.The method takes airspace as the research object,starts with actual flight characteristics,and applies conclusions of random waypoint mobility model.Building a connectivity model by establishing Airspace Unit Circle(AUC) from the perspective of circle-circle coverage,the method obtains a theory of airspace network connectivity.Experiment demonstrates its correctness.Finally,according to the actual condition simulation,relationship between the number of aircraft,communication radius,and the flight area under connectivity probabilities is achieved,results provide reference for creating a network that under certain aerial combat condition.
基金supported in part by 973 program under con-tract 2007CB307101National High Technology of China ("863 program") under contract No. 2008AA01A326 National Natural Science Foundation of China under Grant No. 60870015 and No. 60833002
文摘Mobile multicast is important for the emerging applications such as mobile video or audio conference and mobile IPTV.Some mobile multicast schemes have been proposed in the past few years, but most of them study the reconstruc-tion of multicast delivery tree, and few consider the group membership management for mobile sub-scribers.In this paper, we propose a new mobile multicast method based on the Two-Hop Multicast Listener Discovery(THMLD) protocol which pro-vides the mobile multicast membership manage-ment function by forwarding the traditional MLD messages to its neighboring subnets.To evaluate its performance, we analyze the THMLD and set up the simulation platform to compare it with the several traditional mobile multicast methods.The results show that THMLD can reduce the multicast join time, and the THMLD-based mobile multicast method can reduce the multicast join delay at a cost of increasing additional multicast maintenance cost.
文摘For the published block cipher algorithm, two kinds of round functions have been researched.Block ciphers in network environments are taking more risks than ever before because of their initialization key's distribution in the internet.The security of block cipher algorithm is affected by linear bias and nonlinear bias which are restricted by confusion layer and diffusion layer.This article takes an approach on how block cipher's two round structures are initially transformed when they fuse into LFSR.The SP structure can be considered two F functions in one Feistel round function which combines both right and left of origin data transformation.Furthermore, the round number linear function and nonlinear function of Feistel and SP structure are compared.The merit of SP structure is that it can fuse in LFSR as a nonlinear filter without memory.
基金Project (No. 602032) supported by the Natural Science Foundationof Zhejiang Province, China
文摘New challenges are introduced when people try to build a general-purpose mobile agent middleware in Grid envi- ronment. In this paper, an instance-oriented security mechanism is proposed to deal with possible security threats in such mobile agent systems. The current security support in Grid Security Infrastructure (GSI) requires the users to delegate their privileges to certain hosts. This host-oriented solution is insecure and inflexible towards mobile agent applications because it cannot prevent delegation abuse and control well the diffusion of damage. Our proposed solution introduces security instance, which is an en- capsulation of one set of authorizations and their validity specifications with respect to the agent’s specific code segments, or even the states and requests. Applications can establish and configure their security framework flexibly on the same platform, through defining instances and operations according to their own logic. Mechanisms are provided to allow users delegating their identity to these instances instead of certain hosts. By adopting this instance-oriented security mechanism, a Grid-based general-purpose MA middleware, Everest, is developed to enhance Globus Toolkit’s security support for mobile agent applications.
基金the National Natural Science Foundation of China under Grant No.60503045and No.60303040
文摘BitTorrent is a very popular Peer-to-Peer file sharing system, which adopts a set of incentive mechanisms to encourage contribution and prevent free-riding. However, we find that BitTorrent’s incentive mechanism can prevent free-riding effectively in a system with a relatively low number of seeds, but may fail in producing a disincentive for free-riding in a system with a high number of seeds. The reason is that BitTorrent does not provide effective mechanisms for seeds to guard against free-riding. Therefore, we propose a seed bandwidth allocation strategy for the BitTorrent system to reduce the effect of seeds on free-riding. Our target is that a downloader which provides more service to the system will be granted a higher benefit than downloaders which provide lower service when some downloaders ask for downloading file from a seed. Finally, simulation results are given, which validate the effectiveness of the proposed strategy.
文摘A distributed QoS (quality of service) -aware source-specific multicast routing protocol—DQSSMR is proposed to increase the successful join ratio and lower the overhead of the control message in QoS required multicast routing. By an improved searching strategy, the cost of message control is reduced and the successful join ratio is increased. The network load is balanced due to the distributed routing operation and the scalability is enhanced further because of the usage of SSM (source- specific multicast) service model in DQSSMR. The analysis results indicate that DQSSMR performs as expected.
基金Supported by the Promotive Research Fund for Excellent Young and Middle-aged Scientists of Shandong Province(No.BS2010DX010)the Project of Higher Educational Science and Technology Program of Shandong Province(No.J12LN36)
文摘In this paper,an Adaptive-Weighted Time-Dimensional and Space-Dimensional(AWTDSD) data aggregation algorithm for a clustered sensor network is proposed for prolonging the lifetime of the network as well as improving the accuracy of the data gathered in the network.AWTDSD contains three phases:(1) the time-dimensional aggregation phase for eliminating the data redundancy;(2) the adaptive-weighted aggregation phase for further aggregating the data as well as improving the accuracy of the aggregated data; and(3) the space-dimensional aggregation phase for reducing the size and the amount of the data transmission to the base station.AWTDSD utilizes the correlations between the sensed data for reducing the data transmission and increasing the data accuracy as well.Experimental result shows that AWTDSD can not only save almost a half of the total energy consumption but also greatly increase the accuracy of the data monitored by the sensors in the clustered network.
基金Supported by the National Basic Research Program of China(973 Program)(No.2011CB302903)the National Natural Science Foundation of China(No.61100213)+3 种基金the Key Program of Natural Science for Universities of Jiangsu Province(No.10KJA510035)the Specialized Research Fund for the Doctoral Program of Higher Education(20113223120007)the Science and Technology Program of Nanjing(201103003)the Postgraduate Innovation Project Foundation of Jiangsu Province(No.CXLX11_0411)
文摘To solve the problems of high memory occupation, low connectivity and poor resiliency against node capture, which existing in the random key pre-distribution techniques while applying to the large scale Wireless Sensor Networks （WSNs）, an Identity-Based Key Agreement Scheme （IBKAS） is proposed based on identity-based encryption and Elliptic Curve Diffie-Hellman （ECDH）. IBKAS can resist man-in-the-middle attacks and node-capture attacks through encrypting the key agreement parameters using identity-based encryption. Theoretical analysis indicates that comparing to the random key pre-distribution techniques, IBKAS achieves significant improvement in key connectivity, communication overhead, memory occupation, and security strength, and also enables efficient secure rekcying and network expansion. Furthermore, we implement IBKAS for TinyOS-2.1.2 based on the MICA2 motes, and the experiment results demonstrate that IBKAS is feasible for infrequent key distribution and rekeying for large scale sensor networks.
文摘The paper analyze and design and implement a remote control system based on network. A computer network remote control system mainly includes server, client and the control information. Server registration information realize the user command; client provides network hardware, software and other system resources, the system response message and then feedback service instruction; control information transmission layer implementation using TCPflP protocol to control information including control of resources and control commands etc.. This paper adopts centralized network control system model, the structure of the network system realize unified observation, control, coordination, and control of high efficiency. The use of key technologies, such as Socket and COM to realize the goal of computer hardware resource control, software resource management and other functions.
文摘The technology innovation cooperation relationship of enterprises has evolved into the representation of complicated network. MATLAB software is used for computer simulation on network evolution process of technology innovation cooperation, and Ucinet characterization analysis software is used to compute characteristic values of simulation network such as power law index of network, average route length and accumulation coefficients. It is compared with the actual network, and the simulation results are analyzed to verify the rationality of the constructed evolution model.
文摘Computer networks have to support an everincreasing array of applications,ranging from cloud computing in datacenters to Internet access for users.In order to meet the various demands,a large number of network devices running different protocols are designed and deployed in networks.
