The advent of parametric design has resulted in a marked increase in the complexity of building.Unfortunately,traditional construction methods make it difficult to meet the needs.Therefore,construction robots have bec...The advent of parametric design has resulted in a marked increase in the complexity of building.Unfortunately,traditional construction methods make it difficult to meet the needs.Therefore,construction robots have become a pivotal production tool in this context.Since the arm span of a single robot usually does not exceed 3 meters,it is not competent for producing large-scale building components.Accordingly,the extension of the robot,s working range is often achieved by external axes.Nevertheless,the coupling control of external axes and robots and their kinematic solution have become key challenges.The primary technical difficulties include customized construction robots,automatic solutions for external axes,fixed axis joints,and specific motion mode control.This paper proposes solutions to these difficulties,introduces the relevant basic concepts and algorithms in detail,and encapsulates these robotics principles and algorithm processes into the Grasshopper plug-in commonly used by architects to form the FURobot software platform.This platform effectively solves the above problems,lowers the threshold for architects,and improves production efficiency.The effectiveness of the algorithm and software in this paper is verified through simulation experiments.展开更多
Software defined optical networking(SDON)is a critical technology for the next generation network with the advantages of programmable control and etc.As one of the key issues of SDON,the security of control plane has ...Software defined optical networking(SDON)is a critical technology for the next generation network with the advantages of programmable control and etc.As one of the key issues of SDON,the security of control plane has also received extensive attention,especially in certain network scenarios with high security requirement.Due to the existence of vulnerabilities and heavy overhead,the existing firewalls and distributed control technologies cannot solve the control plane security problem well.In this paper,we propose a distributed control architecture for SDON using the blockchain technique(BlockCtrl).The proposed BlockCtrl model introduces the advantages of blockchain into SDON to achieve a high-efficiency fault tolerant control.We have evaluated the performance of our proposed architecture and compared it to the existing models with respect to various metrics including processing rate,recovery latency and etc.The numerical results show that the BlockCtrl is capable of attacks detection and fault tolerant control in SDON with high performance on resource utilization and service correlation.展开更多
The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wish...The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wishes more information about the measurement and the collected data. This situation sug- gested an improvement of the software and computer hardware. The goal was to develop a small useful PC tool that eliminates these deficits. However, it resulted in a very extensive application software, which was developed during 2011-2015. Along the way, some unwanted effects of the original control circuit were detected. Therefore as a last step a complete new control circuit for the feedback system was developed. This new circuit is fast and smooth and without resonance effects to the system. The algorithm parameters can be specifically adapted to the specific gravity meter. The software has a security system that ensures the user, depending on his level of knowledge, a limited access to the software options. Furthermore, a customer project management system is integrated. The observer, the gravity meters, the projects and maps can be assigned. Several ZLS Burris gravity meters can be managed. A large station data management is integrated. Every station has up to more than twenty parameters, such as the mandatory coordinates or supplementary pictures of the station. External storage and documentation of the measurements are possible with extra modules. In addition the maintenance of the gravity meter system is significantly improved. The motor control of the early ZLS Burris gravity meter is also improved. The complete rotation is displayed on the screen. Finally, two survey examples show the advantages of the software related to the accuracy and the time needed for a measurement.展开更多
With the rapid development of software technology, software vulnerability has become a major threat to computer security. The timely detection and repair of potential vulnerabilities in software, are of great signific...With the rapid development of software technology, software vulnerability has become a major threat to computer security. The timely detection and repair of potential vulnerabilities in software, are of great significance in reducing system crashes and maintaining system security and integrity. This paper focuses on detecting three common types of vulnerabilities: Unused_Variable, Use_of_Uninitialized_Variable, and Use_After_ Free. We propose a method for software vulnerability detection based on an improved control flow graph(ICFG) and several predicates of vulnerability properties for each type of vulnerability. We also define a set of grammar rules for analyzing and deriving the three mentioned types of vulnerabilities, and design three vulnerability detection algorithms to guide the process of vulnerability detection. In addition, we conduct cases studies of the three mentioned types of vulnerabilities with real vulnerability program segments from Common Weakness Enumeration(CWE). The results of the studies show that the proposed method can detect the vulnerability in the tested program segments. Finally, we conduct manual analysis and experiments on detecting the three types of vulnerability program segments(30 examples for each type) from CWE, to compare the vulnerability detection effectiveness of the proposed method with that of the existing detection tool Cpp Check. The results show that the proposed method performs better. In summary, the method proposed in this paper has certain feasibility and effectiveness in detecting the three mentioned types of vulnerabilities, and it will also have guiding significance for the detection of other common vulnerabilities.展开更多
A new method that designs and implements the component-based distributed & hierarchical flexible manufacturing control software is described with a component concept in this paper. The proposed method takes aim at...A new method that designs and implements the component-based distributed & hierarchical flexible manufacturing control software is described with a component concept in this paper. The proposed method takes aim at improving the flexibility and reliability of the control system. On the basis of describing the concepts of component-based software and the distributed object technology, the architecture of the component-based software of the control system is suggested with the Common Object Request Broker Architecture (CORBA). And then, we propose a design method for component-based distributed & hierarchical flexible manufacturing control system. Finally, to verify the software design method, a prototype flexible manufacturing control system software has been implemented in Orbix 2.3c, VC + + 6. 0 and has been tested in connection with the physical flexible manufacturing shop at the WuXi Professional Institute.展开更多
In order to improve the scalability and reliability of Software Defined Networking(SDN),many studies use multiple controllers to constitute logically centralized control plane to provide load balancing and fail over.I...In order to improve the scalability and reliability of Software Defined Networking(SDN),many studies use multiple controllers to constitute logically centralized control plane to provide load balancing and fail over.In this paper,we develop a flexible dormant multi-controller model based on the centralized multi-controller architecture.The dormant multi-controller model allows part of controllers to enter the dormant state under light traffic condition for saving system cost.Meanwhile,through queueing analysis,various performance measures of the system can be obtained.Moreover,we analyze the real traffic of China Education Network and use the results as the parameters of computer simulation and verify the effects of parameters on the system characteristics.Finally,a total expected cost function is established,and genetic algorithm is employed to find the optimal values of various parameters to minimize system cost for the deployment decision making.展开更多
The controller is indispensable in software-defined networking(SDN).With several features,controllers monitor the network and respond promptly to dynamic changes.Their performance affects the quality-of-service(QoS)in...The controller is indispensable in software-defined networking(SDN).With several features,controllers monitor the network and respond promptly to dynamic changes.Their performance affects the quality-of-service(QoS)in SDN.Every controller supports a set of features.However,the support of the features may be more prominent in one controller.Moreover,a single controller leads to performance,single-point-of-failure(SPOF),and scalability problems.To overcome this,a controller with an optimum feature set must be available for SDN.Furthermore,a cluster of optimum feature set controllers will overcome an SPOF and improve the QoS in SDN.Herein,leveraging an analytical network process(ANP),we rank SDN controllers regarding their supporting features and create a hierarchical control plane based cluster(HCPC)of the highly ranked controller computed using the ANP,evaluating their performance for the OS3E topology.The results demonstrated in Mininet reveal that a HCPC environment with an optimum controller achieves an improved QoS.Moreover,the experimental results validated in Mininet show that our proposed approach surpasses the existing distributed controller clustering(DCC)schemes in terms of several performance metrics i.e.,delay,jitter,throughput,load balancing,scalability and CPU(central processing unit)utilization.展开更多
By decoupling control plane and data plane,Software-Defined Networking(SDN) approach simplifies network management and speeds up network innovations.These benefits have led not only to prototypes,but also real SDN dep...By decoupling control plane and data plane,Software-Defined Networking(SDN) approach simplifies network management and speeds up network innovations.These benefits have led not only to prototypes,but also real SDN deployments.For wide-area SDN deployments,multiple controllers are often required,and the placement of these controllers becomes a particularly important task in the SDN context.This paper studies the problem of placing controllers in SDNs,so as to maximize the reliability of SDN control networks.We present a novel metric,called expected percentage of control path loss,to characterize the reliability of SDN control networks.We formulate the reliability-aware control placement problem,prove its NP-hardness,and examine several placement algorithms that can solve this problem.Through extensive simulations using real topologies,we show how the number of controllers and their placement influence the reliability of SDN control networks.Besides,we also found that,through strategic controller placement,the reliability of SDN control networks can be significantly improved without introducing unacceptable switch-to-controller latencies.展开更多
The emergence of a new network architecture,known as Software Defined Networking(SDN),in the last two decades has overcome some drawbacks of traditional networks in terms of performance,scalability,reliability,securit...The emergence of a new network architecture,known as Software Defined Networking(SDN),in the last two decades has overcome some drawbacks of traditional networks in terms of performance,scalability,reliability,security,and network management.However,the SDN is vulnerable to security threats that target its controller,such as low-rate Distributed Denial of Service(DDoS)attacks,The low-rate DDoS attack is one of the most prevalent attacks that poses a severe threat to SDN network security because the controller is a vital architecture component.Therefore,there is an urgent need to propose a detection approach for this type of attack with a high detection rate and low false-positive rates.Thus,this paper proposes an approach to detect low-rate DDoS attacks on the SDN controller by adapting a dynamic threshold.The proposed approach has been evaluated using four simulation scenarios covering a combination of low-rate DDoS attacks against the SDN controller involving(i)a single host attack targeting a single victim;(ii)a single host attack targeting multiple victims;(iii)multiple hosts attack targeting a single victim;and(iv)multiple hosts attack targeting multiple victims.The proposed approach’s average detection rates are 96.65%,91.83%,96.17%,and 95.33%for the above scenarios,respectively;and its average false-positive rates are 3.33%,8.17%,3.83%,and 4.67%for similar scenarios,respectively.The comparison between the proposed approach and two existing approaches showed that it outperformed them in both categories.展开更多
Controller placement problem(CPP)is a critical issue in software defined wireless networks(SDWN).Due to the limited power of wireless devices,CPP is facing the challenge of energy efficiency in SDWN.Nevertheless,the r...Controller placement problem(CPP)is a critical issue in software defined wireless networks(SDWN).Due to the limited power of wireless devices,CPP is facing the challenge of energy efficiency in SDWN.Nevertheless,the related research on CPP in SDWN hasn’t modeled the energy consumption of controllers so far.To prolong the lifetime of SDWN and improve the practicability of research,we rebuilt a CPP model considering the minimal transmitted power of controllers.An adaptive controller placement algorithm(ACPA)is proposed with the following two stages.First,data field method is adopted to determine sub-networks for different network topologies.Second,for each sub-network we adopt an exhaustive method to find the optimal location which meets the minimal average transmitted power to place controller.Compared with the other algorithms,the effectiveness and efficiency of the proposed scheme are validated through simulation.展开更多
To improve the reusable and configurable ability of computer numerical control ( CNC ) software, a new method to construct reusable model of CNC software with object-oriented (OO) technology is proposed. Based on anal...To improve the reusable and configurable ability of computer numerical control ( CNC ) software, a new method to construct reusable model of CNC software with object-oriented (OO) technology is proposed. Based on analyzing function of CNC software, the article presents how to construct a general class library of CNC software with OO technology. Most function modules of CNC software can he reused because of inheritable capability of classes. Besides, the article analyzes the object relational model in request/report mode, and multitask concurrent management model, which can he applied on double-CPU hardware platform and Windows 95/NT environment. Finally, the method has been successfully applied on a turning CNC system and a milling CNC system, and some function modules have been reused.展开更多
The control and data planes are decoupled in software-defined networking(SDN),which enables both planes to evolve independently,and brings about many advantages such as high flexibility,programmability,and rapid imple...The control and data planes are decoupled in software-defined networking(SDN),which enables both planes to evolve independently,and brings about many advantages such as high flexibility,programmability,and rapid implementation of new network protocols.However,in order to improve the scalability of the control plane at present,some control functionalities are added to the data plane,which is probably to impact on the generality of the data plane.The key challenge of adding control functionalities to the data plane is to strike a careful balance between the generality of the data plane and the scalability of the control plane.We propose some basic principles that both control and data planes should comply with,based on the evolutionary trend of SDN.Moreover,we take two approaches for reference according to the principles,viewed from the control messages in OpenFlow-based SDN.Our evaluations demonstrate that the approaches can maintain the generality of the data plane and improve the scalability of the control plane.展开更多
This paper discusses the design and software-in-theloop implementation of adaptive formation controllers for fixedwing unmanned aerial vehicles(UAVs) with parametric uncertainty in their structure, namely uncertain ma...This paper discusses the design and software-in-theloop implementation of adaptive formation controllers for fixedwing unmanned aerial vehicles(UAVs) with parametric uncertainty in their structure, namely uncertain mass and inertia. In fact, when aiming at autonomous flight, such parameters cannot assumed to be known as they might vary during the mission(e.g.depending on the payload). Modeling and autopilot design for such autonomous fixed-wing UAVs are presented. The modeling is implemented in Matlab, while the autopilot is based on ArduPilot, a popular open-source autopilot suite. Specifically, the ArduP ilot functionalities are emulated in Matlab according to the Ardupilot documentation and code, which allows us to perform software-in-the-loop simulations of teams of UAVs embedded with actual autopilot protocols. An overview of realtime path planning, trajectory tracking and formation control resulting from the proposed platform is given. The software-inthe-loop simulations show the capability of achieving different UAV formations while handling uncertain mass and inertia.展开更多
Many industrial companies and researchers are looking for more efficient model driven engineering approaches (MDE) in software engineering of manufacturing automation systems (MS) especially for logic control programm...Many industrial companies and researchers are looking for more efficient model driven engineering approaches (MDE) in software engineering of manufacturing automation systems (MS) especially for logic control programming, but are uncertain about the applicability and effort needed to implement those approaches in comparison to classical Programmable Logic Controller?(PLC) programming with IEC 61131-3. The paper summarizes results of usability experiments evaluating UML and SysML as software engineering notations for a MDE applied in the domain of manufacturing systems. Modeling MS needs to cover the domain specific characteristics,?i.e.?hybrid process, real time requirements and communication requirements. In addition the paper presents factors, constraint and practical experience for the development of further usability experiments. The paper gives examples of notational expressiveness and weaknesses of UML and SysML. The appendix delivers detailed master models, representing the correct best suited model, and evaluation schemes of the experiment, which is helpful if setting up own empirical experiments.展开更多
Supervisory control is a very popular paradigm for computer-controlled systems. Knowledge and tracking the control effect of every control operation is crucial to the control tasks. In the paper, we present a message-...Supervisory control is a very popular paradigm for computer-controlled systems. Knowledge and tracking the control effect of every control operation is crucial to the control tasks. In the paper, we present a message-array-based mechanism to track control effects in supervisory control software. A novel data type, message array, is designed to efficiently support this tracking mechanism. The operation algorithms, adding algorithm （AA）, removing algorithm （RA）, and scheduler algorithm （SA） are proposed to operate the tracking messages in message array, which forms the special first input X output （FIXO） strategy of message array. Automatically tracking, recording, and rolling back are the characteristics of our tracking mechanism. We implement this messagearray-based mechanism on the famous human machine interface （HMI） software platform-proficy iFix, and construct experiments to evaluate the performance of the mechanism in various cases. The results show our mechanism can be well satisfied with supervisory control software.展开更多
In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication systems.Existing research ha...In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication systems.Existing research has concentrated largely on factors such as reliability,latency,controller capacity,propagation delay,and energy consumption.However,SDNs are vulnerable to distributed denial of service(DDoS)attacks that interfere with legitimate use of the network.The ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design,especially in critical applications such as military,health care,and financial services networks requiring high availability.We propose a mathematical model for planning the deployment of SDN smart backup controllers(SBCs)to preserve service in the presence of DDoS attacks.Given a number of input parameters,our model has two distinct capabilities.First,it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating conditions.Second,it recommends an optimal number of smart backup controllers for use with different levels of DDoS attacks.The goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the parameters.Our simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost.展开更多
Time-triggered （TT） embedded software pattern is well accepted in aerospace industry for its high reliability. Fi-nite-state-machine （FSM） design method is widely used for its high efficiency and predictable behav...Time-triggered （TT） embedded software pattern is well accepted in aerospace industry for its high reliability. Fi-nite-state-machine （FSM） design method is widely used for its high efficiency and predictable behavior. In this paper, the time-triggered and state-machine combination software architecture is implemented for a 25 kg thrust micro turbine engine （MTE） used for unmanned aerial vehicle （UAV） system; also model-based-design development workflow for airworthiness software directive DO-178B is utilized. Experimental results show that time-triggered state-machine software architecture and development method could shorten the system development time, reduce the system test cost and make the turbine engine easily comply with the airworthiness rules.展开更多
When applying Software-Defined Networks(SDN) to WANs,the SDN flexibility enables the cross-domain control to achieve a better control scalability.However,the control consistence is required by all the cross-domain ser...When applying Software-Defined Networks(SDN) to WANs,the SDN flexibility enables the cross-domain control to achieve a better control scalability.However,the control consistence is required by all the cross-domain services,to ensure the data plane configured in consensus for different domains.Such consistence process is complicated by potential failure and errors of WANs.In this paper,we propose a consistence layer to actively and passively snapshot the cross-domain control states,to reduce the complexities of service realizations.We implement the layer and evaluate performance in the PlanetLab testbed for the WAN emulation.The testbed conditions are extremely enlarged comparing to the real network.The results show its scalability,reliability and responsiveness in dealing with the control dynamics.In the normalized results,the active and passive snapshots are executed with the mean times of 1.873 s and 105 ms in135 controllers,indicating its readiness to be used in the real network.展开更多
This paper proposes a generic high-performance and low-time-overhead software control flow checking solution, graph-tree-based control flow checking （GTCFC） for space-borne commercial-off-the-shelf （COTS） processo...This paper proposes a generic high-performance and low-time-overhead software control flow checking solution, graph-tree-based control flow checking （GTCFC） for space-borne commercial-off-the-shelf （COTS） processors. A graph tree data structure with a topology similar to common trees is introduced to transform the control flow graphs of target programs. This together with design of IDs and signatures of its vertices and edges allows for an easy check of legality of actual branching during target program execution. As a result, the algorithm not only is capable of detecting all single and multiple branching errors with low latency and time overheads along with a linear-complexity space overhead, but also remains generic among arbitrary instruction sets and independent of any specific hardware. Tests of the algorithm using a COTS-processor-based onboard computer （OBC） of in-service ZDPS-1A pico-satellite products show that GTCFC can detect over 90% of the randomly injected and all-pattern-covering branching errors for different types of target programs, with performance and overheads consistent with the theoretical analysis; and beats well-established preeminent control flow checking algorithms in these dimensions. Furthermore, it is validated that GTCGC not only can be accommodated in pico-satellites conveniently with still sufficient system margins left, but also has the ability to minimize the risk of control flow errors being undetected in their space missions. Therefore, due to its effectiveness, efficiency, and compatibility, the GTCFC solution is ready for applications on COTS processors on pico-satellites in their real space missions.展开更多
A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project r...A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project risks. A model for optimizing software risk control is given, a discrete optimization algorithm based on dynamic programruing is proposed and an example of using above method to solve a problem is also included in this paper. By improving the old passive post-project control into an active effective preaction, this new method can greatly promote the possibility of success of software projects.展开更多
基金National Key R&D Program of China(Nos.2023YFC3806900,2022YFE0141400)。
文摘The advent of parametric design has resulted in a marked increase in the complexity of building.Unfortunately,traditional construction methods make it difficult to meet the needs.Therefore,construction robots have become a pivotal production tool in this context.Since the arm span of a single robot usually does not exceed 3 meters,it is not competent for producing large-scale building components.Accordingly,the extension of the robot,s working range is often achieved by external axes.Nevertheless,the coupling control of external axes and robots and their kinematic solution have become key challenges.The primary technical difficulties include customized construction robots,automatic solutions for external axes,fixed axis joints,and specific motion mode control.This paper proposes solutions to these difficulties,introduces the relevant basic concepts and algorithms in detail,and encapsulates these robotics principles and algorithm processes into the Grasshopper plug-in commonly used by architects to form the FURobot software platform.This platform effectively solves the above problems,lowers the threshold for architects,and improves production efficiency.The effectiveness of the algorithm and software in this paper is verified through simulation experiments.
基金supported in part by NSFC project(61871056)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)+1 种基金Fundamental Research Funds for the Central Universities(2018XKJC06)Open Fund of SKL of IPOC(BUPT)(IPOC2018A001)
文摘Software defined optical networking(SDON)is a critical technology for the next generation network with the advantages of programmable control and etc.As one of the key issues of SDON,the security of control plane has also received extensive attention,especially in certain network scenarios with high security requirement.Due to the existence of vulnerabilities and heavy overhead,the existing firewalls and distributed control technologies cannot solve the control plane security problem well.In this paper,we propose a distributed control architecture for SDON using the blockchain technique(BlockCtrl).The proposed BlockCtrl model introduces the advantages of blockchain into SDON to achieve a high-efficiency fault tolerant control.We have evaluated the performance of our proposed architecture and compared it to the existing models with respect to various metrics including processing rate,recovery latency and etc.The numerical results show that the BlockCtrl is capable of attacks detection and fault tolerant control in SDON with high performance on resource utilization and service correlation.
文摘The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wishes more information about the measurement and the collected data. This situation sug- gested an improvement of the software and computer hardware. The goal was to develop a small useful PC tool that eliminates these deficits. However, it resulted in a very extensive application software, which was developed during 2011-2015. Along the way, some unwanted effects of the original control circuit were detected. Therefore as a last step a complete new control circuit for the feedback system was developed. This new circuit is fast and smooth and without resonance effects to the system. The algorithm parameters can be specifically adapted to the specific gravity meter. The software has a security system that ensures the user, depending on his level of knowledge, a limited access to the software options. Furthermore, a customer project management system is integrated. The observer, the gravity meters, the projects and maps can be assigned. Several ZLS Burris gravity meters can be managed. A large station data management is integrated. Every station has up to more than twenty parameters, such as the mandatory coordinates or supplementary pictures of the station. External storage and documentation of the measurements are possible with extra modules. In addition the maintenance of the gravity meter system is significantly improved. The motor control of the early ZLS Burris gravity meter is also improved. The complete rotation is displayed on the screen. Finally, two survey examples show the advantages of the software related to the accuracy and the time needed for a measurement.
基金Supported by the National Natural Science Foundation of China(61202110 and 61502205)the Project of Jiangsu Provincial Six Talent Peaks(XYDXXJS-016)
文摘With the rapid development of software technology, software vulnerability has become a major threat to computer security. The timely detection and repair of potential vulnerabilities in software, are of great significance in reducing system crashes and maintaining system security and integrity. This paper focuses on detecting three common types of vulnerabilities: Unused_Variable, Use_of_Uninitialized_Variable, and Use_After_ Free. We propose a method for software vulnerability detection based on an improved control flow graph(ICFG) and several predicates of vulnerability properties for each type of vulnerability. We also define a set of grammar rules for analyzing and deriving the three mentioned types of vulnerabilities, and design three vulnerability detection algorithms to guide the process of vulnerability detection. In addition, we conduct cases studies of the three mentioned types of vulnerabilities with real vulnerability program segments from Common Weakness Enumeration(CWE). The results of the studies show that the proposed method can detect the vulnerability in the tested program segments. Finally, we conduct manual analysis and experiments on detecting the three types of vulnerability program segments(30 examples for each type) from CWE, to compare the vulnerability detection effectiveness of the proposed method with that of the existing detection tool Cpp Check. The results show that the proposed method performs better. In summary, the method proposed in this paper has certain feasibility and effectiveness in detecting the three mentioned types of vulnerabilities, and it will also have guiding significance for the detection of other common vulnerabilities.
基金Supported by National High Technology Development plan(Item No.:2001AA412250)and Shanghai Science & Technology Development Project(Item No.:02FK04)
文摘A new method that designs and implements the component-based distributed & hierarchical flexible manufacturing control software is described with a component concept in this paper. The proposed method takes aim at improving the flexibility and reliability of the control system. On the basis of describing the concepts of component-based software and the distributed object technology, the architecture of the component-based software of the control system is suggested with the Common Object Request Broker Architecture (CORBA). And then, we propose a design method for component-based distributed & hierarchical flexible manufacturing control system. Finally, to verify the software design method, a prototype flexible manufacturing control system software has been implemented in Orbix 2.3c, VC + + 6. 0 and has been tested in connection with the physical flexible manufacturing shop at the WuXi Professional Institute.
基金the National High-tech R&D Program ("863" Program) of China，the National Science Foundation of China，National Science & Technology Pillar Program of China，the National Science Foundation of China，the Post-Doctoral Funding of China，Tsinghua-Huawei joint research project
文摘In order to improve the scalability and reliability of Software Defined Networking(SDN),many studies use multiple controllers to constitute logically centralized control plane to provide load balancing and fail over.In this paper,we develop a flexible dormant multi-controller model based on the centralized multi-controller architecture.The dormant multi-controller model allows part of controllers to enter the dormant state under light traffic condition for saving system cost.Meanwhile,through queueing analysis,various performance measures of the system can be obtained.Moreover,we analyze the real traffic of China Education Network and use the results as the parameters of computer simulation and verify the effects of parameters on the system characteristics.Finally,a total expected cost function is established,and genetic algorithm is employed to find the optimal values of various parameters to minimize system cost for the deployment decision making.
基金supported by the MSIT(Ministry of Science and ICT),Korea,under the ITRC(Information Technology Research Center)support program(IITP-2020-2018-0-01431)supervised by the IITP(Institute for Information&Communications Technology Planning&Evaluation).
文摘The controller is indispensable in software-defined networking(SDN).With several features,controllers monitor the network and respond promptly to dynamic changes.Their performance affects the quality-of-service(QoS)in SDN.Every controller supports a set of features.However,the support of the features may be more prominent in one controller.Moreover,a single controller leads to performance,single-point-of-failure(SPOF),and scalability problems.To overcome this,a controller with an optimum feature set must be available for SDN.Furthermore,a cluster of optimum feature set controllers will overcome an SPOF and improve the QoS in SDN.Herein,leveraging an analytical network process(ANP),we rank SDN controllers regarding their supporting features and create a hierarchical control plane based cluster(HCPC)of the highly ranked controller computed using the ANP,evaluating their performance for the OS3E topology.The results demonstrated in Mininet reveal that a HCPC environment with an optimum controller achieves an improved QoS.Moreover,the experimental results validated in Mininet show that our proposed approach surpasses the existing distributed controller clustering(DCC)schemes in terms of several performance metrics i.e.,delay,jitter,throughput,load balancing,scalability and CPU(central processing unit)utilization.
基金supported in part by the National High Technology Research and Development Program(863 Program)of China under Grant No.2011AA01A101the National High Technology Research and Development Program(863 Program)of China under Grant No.2013AA01330the National High Technology Research and Development Program(863 Program)of China under Grant No.2013AA013303
文摘By decoupling control plane and data plane,Software-Defined Networking(SDN) approach simplifies network management and speeds up network innovations.These benefits have led not only to prototypes,but also real SDN deployments.For wide-area SDN deployments,multiple controllers are often required,and the placement of these controllers becomes a particularly important task in the SDN context.This paper studies the problem of placing controllers in SDNs,so as to maximize the reliability of SDN control networks.We present a novel metric,called expected percentage of control path loss,to characterize the reliability of SDN control networks.We formulate the reliability-aware control placement problem,prove its NP-hardness,and examine several placement algorithms that can solve this problem.Through extensive simulations using real topologies,we show how the number of controllers and their placement influence the reliability of SDN control networks.Besides,we also found that,through strategic controller placement,the reliability of SDN control networks can be significantly improved without introducing unacceptable switch-to-controller latencies.
基金This work was supported by Universiti Sains Malaysia under external grant(Grant Number 304/PNAV/650958/U154).
文摘The emergence of a new network architecture,known as Software Defined Networking(SDN),in the last two decades has overcome some drawbacks of traditional networks in terms of performance,scalability,reliability,security,and network management.However,the SDN is vulnerable to security threats that target its controller,such as low-rate Distributed Denial of Service(DDoS)attacks,The low-rate DDoS attack is one of the most prevalent attacks that poses a severe threat to SDN network security because the controller is a vital architecture component.Therefore,there is an urgent need to propose a detection approach for this type of attack with a high detection rate and low false-positive rates.Thus,this paper proposes an approach to detect low-rate DDoS attacks on the SDN controller by adapting a dynamic threshold.The proposed approach has been evaluated using four simulation scenarios covering a combination of low-rate DDoS attacks against the SDN controller involving(i)a single host attack targeting a single victim;(ii)a single host attack targeting multiple victims;(iii)multiple hosts attack targeting a single victim;and(iv)multiple hosts attack targeting multiple victims.The proposed approach’s average detection rates are 96.65%,91.83%,96.17%,and 95.33%for the above scenarios,respectively;and its average false-positive rates are 3.33%,8.17%,3.83%,and 4.67%for similar scenarios,respectively.The comparison between the proposed approach and two existing approaches showed that it outperformed them in both categories.
基金supported by the Open Research Fund of Key Laboratory of Space Utilization,Chinese Academy of Sciences(No.LSU-KFJJ-2018-06)the International Research Cooperation Seed Fund of Beijing University of Technology(No.2018B41)
文摘Controller placement problem(CPP)is a critical issue in software defined wireless networks(SDWN).Due to the limited power of wireless devices,CPP is facing the challenge of energy efficiency in SDWN.Nevertheless,the related research on CPP in SDWN hasn’t modeled the energy consumption of controllers so far.To prolong the lifetime of SDWN and improve the practicability of research,we rebuilt a CPP model considering the minimal transmitted power of controllers.An adaptive controller placement algorithm(ACPA)is proposed with the following two stages.First,data field method is adopted to determine sub-networks for different network topologies.Second,for each sub-network we adopt an exhaustive method to find the optimal location which meets the minimal average transmitted power to place controller.Compared with the other algorithms,the effectiveness and efficiency of the proposed scheme are validated through simulation.
基金Supported by Science and Technology Development Foundation of Shanghai Science and Technology Committee(995107017)
文摘To improve the reusable and configurable ability of computer numerical control ( CNC ) software, a new method to construct reusable model of CNC software with object-oriented (OO) technology is proposed. Based on analyzing function of CNC software, the article presents how to construct a general class library of CNC software with OO technology. Most function modules of CNC software can he reused because of inheritable capability of classes. Besides, the article analyzes the object relational model in request/report mode, and multitask concurrent management model, which can he applied on double-CPU hardware platform and Windows 95/NT environment. Finally, the method has been successfully applied on a turning CNC system and a milling CNC system, and some function modules have been reused.
文摘The control and data planes are decoupled in software-defined networking(SDN),which enables both planes to evolve independently,and brings about many advantages such as high flexibility,programmability,and rapid implementation of new network protocols.However,in order to improve the scalability of the control plane at present,some control functionalities are added to the data plane,which is probably to impact on the generality of the data plane.The key challenge of adding control functionalities to the data plane is to strike a careful balance between the generality of the data plane and the scalability of the control plane.We propose some basic principles that both control and data planes should comply with,based on the evolutionary trend of SDN.Moreover,we take two approaches for reference according to the principles,viewed from the control messages in OpenFlow-based SDN.Our evaluations demonstrate that the approaches can maintain the generality of the data plane and improve the scalability of the control plane.
基金supported by the Fundamental Research Funds for the Central Universities(4007019109)(RECON-STRUCT)the Special Guiding Funds for Double First-class(4007019201)the Joint TU Delft-CSSC Project ‘Multi-agent Coordination with Networked Constraints’(MULTI-COORD)
文摘This paper discusses the design and software-in-theloop implementation of adaptive formation controllers for fixedwing unmanned aerial vehicles(UAVs) with parametric uncertainty in their structure, namely uncertain mass and inertia. In fact, when aiming at autonomous flight, such parameters cannot assumed to be known as they might vary during the mission(e.g.depending on the payload). Modeling and autopilot design for such autonomous fixed-wing UAVs are presented. The modeling is implemented in Matlab, while the autopilot is based on ArduPilot, a popular open-source autopilot suite. Specifically, the ArduP ilot functionalities are emulated in Matlab according to the Ardupilot documentation and code, which allows us to perform software-in-the-loop simulations of teams of UAVs embedded with actual autopilot protocols. An overview of realtime path planning, trajectory tracking and formation control resulting from the proposed platform is given. The software-inthe-loop simulations show the capability of achieving different UAV formations while handling uncertain mass and inertia.
文摘Many industrial companies and researchers are looking for more efficient model driven engineering approaches (MDE) in software engineering of manufacturing automation systems (MS) especially for logic control programming, but are uncertain about the applicability and effort needed to implement those approaches in comparison to classical Programmable Logic Controller?(PLC) programming with IEC 61131-3. The paper summarizes results of usability experiments evaluating UML and SysML as software engineering notations for a MDE applied in the domain of manufacturing systems. Modeling MS needs to cover the domain specific characteristics,?i.e.?hybrid process, real time requirements and communication requirements. In addition the paper presents factors, constraint and practical experience for the development of further usability experiments. The paper gives examples of notational expressiveness and weaknesses of UML and SysML. The appendix delivers detailed master models, representing the correct best suited model, and evaluation schemes of the experiment, which is helpful if setting up own empirical experiments.
文摘Supervisory control is a very popular paradigm for computer-controlled systems. Knowledge and tracking the control effect of every control operation is crucial to the control tasks. In the paper, we present a message-array-based mechanism to track control effects in supervisory control software. A novel data type, message array, is designed to efficiently support this tracking mechanism. The operation algorithms, adding algorithm （AA）, removing algorithm （RA）, and scheduler algorithm （SA） are proposed to operate the tracking messages in message array, which forms the special first input X output （FIXO） strategy of message array. Automatically tracking, recording, and rolling back are the characteristics of our tracking mechanism. We implement this messagearray-based mechanism on the famous human machine interface （HMI） software platform-proficy iFix, and construct experiments to evaluate the performance of the mechanism in various cases. The results show our mechanism can be well satisfied with supervisory control software.
基金This research work was funded by TMR&D Sdn Bhd under project code RDTC160902.
文摘In software-defined networks(SDNs),controller placement is a critical factor in the design and planning for the future Internet of Things(IoT),telecommunication,and satellite communication systems.Existing research has concentrated largely on factors such as reliability,latency,controller capacity,propagation delay,and energy consumption.However,SDNs are vulnerable to distributed denial of service(DDoS)attacks that interfere with legitimate use of the network.The ever-increasing frequency of DDoS attacks has made it necessary to consider them in network design,especially in critical applications such as military,health care,and financial services networks requiring high availability.We propose a mathematical model for planning the deployment of SDN smart backup controllers(SBCs)to preserve service in the presence of DDoS attacks.Given a number of input parameters,our model has two distinct capabilities.First,it determines the optimal number of primary controllers to place at specific locations or nodes under normal operating conditions.Second,it recommends an optimal number of smart backup controllers for use with different levels of DDoS attacks.The goal of the model is to improve resistance to DDoS attacks while optimizing the overall cost based on the parameters.Our simulated results demonstrate that the model is useful in planning for SDN reliability in the presence of DDoS attacks while managing the overall cost.
文摘Time-triggered （TT） embedded software pattern is well accepted in aerospace industry for its high reliability. Fi-nite-state-machine （FSM） design method is widely used for its high efficiency and predictable behavior. In this paper, the time-triggered and state-machine combination software architecture is implemented for a 25 kg thrust micro turbine engine （MTE） used for unmanned aerial vehicle （UAV） system; also model-based-design development workflow for airworthiness software directive DO-178B is utilized. Experimental results show that time-triggered state-machine software architecture and development method could shorten the system development time, reduce the system test cost and make the turbine engine easily comply with the airworthiness rules.
基金supported by the National Basic Research Program of China (2012CB315903)the Program for Key Science and Technology Innovation Team of Zhejiang Province(2011R50010,2013TD20)+3 种基金the National High Technology Research Program of China(2015AA016103)the National Natural Science Foundation of China(61379118)the Research Fund of ZTE CorporationJiaxing Science and Technology Project (No.2014AY21021)
文摘When applying Software-Defined Networks(SDN) to WANs,the SDN flexibility enables the cross-domain control to achieve a better control scalability.However,the control consistence is required by all the cross-domain services,to ensure the data plane configured in consensus for different domains.Such consistence process is complicated by potential failure and errors of WANs.In this paper,we propose a consistence layer to actively and passively snapshot the cross-domain control states,to reduce the complexities of service realizations.We implement the layer and evaluate performance in the PlanetLab testbed for the WAN emulation.The testbed conditions are extremely enlarged comparing to the real network.The results show its scalability,reliability and responsiveness in dealing with the control dynamics.In the normalized results,the active and passive snapshots are executed with the mean times of 1.873 s and 105 ms in135 controllers,indicating its readiness to be used in the real network.
基金supported by National Natural Science Foundation of China (No. 60904090)
文摘This paper proposes a generic high-performance and low-time-overhead software control flow checking solution, graph-tree-based control flow checking （GTCFC） for space-borne commercial-off-the-shelf （COTS） processors. A graph tree data structure with a topology similar to common trees is introduced to transform the control flow graphs of target programs. This together with design of IDs and signatures of its vertices and edges allows for an easy check of legality of actual branching during target program execution. As a result, the algorithm not only is capable of detecting all single and multiple branching errors with low latency and time overheads along with a linear-complexity space overhead, but also remains generic among arbitrary instruction sets and independent of any specific hardware. Tests of the algorithm using a COTS-processor-based onboard computer （OBC） of in-service ZDPS-1A pico-satellite products show that GTCFC can detect over 90% of the randomly injected and all-pattern-covering branching errors for different types of target programs, with performance and overheads consistent with the theoretical analysis; and beats well-established preeminent control flow checking algorithms in these dimensions. Furthermore, it is validated that GTCGC not only can be accommodated in pico-satellites conveniently with still sufficient system margins left, but also has the ability to minimize the risk of control flow errors being undetected in their space missions. Therefore, due to its effectiveness, efficiency, and compatibility, the GTCFC solution is ready for applications on COTS processors on pico-satellites in their real space missions.
基金Supported bythe Plan of New Technology Projectsin China National Packaging Corporation2005 (05ZBJA011)the Na-tional Natural Science Foundation of China (60373062) National Sci-ence Foundation of Hunan Province(04JJ3052)
文摘A new approach for assessing and optimizing software project process based on software risk control presented, which evaluates and optimizes software project process from the view of controlling the software project risks. A model for optimizing software risk control is given, a discrete optimization algorithm based on dynamic programruing is proposed and an example of using above method to solve a problem is also included in this paper. By improving the old passive post-project control into an active effective preaction, this new method can greatly promote the possibility of success of software projects.
