An automatic well test interpretation method for radial composite reservoirs based on convolutional neural network(CNN) is proposed, and its effectiveness and accuracy are verified by actual field data. In this paper,...An automatic well test interpretation method for radial composite reservoirs based on convolutional neural network(CNN) is proposed, and its effectiveness and accuracy are verified by actual field data. In this paper, based on the data transformed by logarithm function and the loss function of mean square error(MSE), the optimal CNN is obtained by reducing the loss function to optimize the network with "dropout" method to avoid over fitting. The trained optimal network can be directly used to interpret the buildup or drawdown pressure data of the well in the radial composite reservoir, that is, the log-log plot of the given measured pressure variation and its derivative data are input into the network, the outputs are corresponding reservoir parameters(mobility ratio, storativity ratio, dimensionless composite radius, and dimensionless group characterizing well storage and skin effects), which realizes the automatic initial fitting of well test interpretation parameters. The method is verified with field measured data of Daqing Oilfield. The research shows that the method has high interpretation accuracy, and it is superior to the analytical method and the least square method.展开更多
Unified modeling language （UML） is a powerful graphical modeling language with intuitional meaning. It provides various diagrams to depict system characteristics and complex environment from different viewpoints and...Unified modeling language （UML） is a powerful graphical modeling language with intuitional meaning. It provides various diagrams to depict system characteristics and complex environment from different viewpoints and different application layers. UML-based software development and modeling environments have been widely accepted in industry, including areas in which safety is an important issue such as spaceflight, defense, automobile, etc. To ensure and improve software quality becomes a main concern in the field. As one of the key techniques for software quality, software testing can effectively detect system faults. UML based software testing based is an important research direction in software engineering. The key to software testing is the generation of test cases. This dissertation studies an approach to generating test cases from UML statecharts.展开更多
The detection system integrates control technology, network technology, video encoding and decoding, video transmiss-ion, multi-single chip microcomputer communication, dat-abase technology, computer software and robo...The detection system integrates control technology, network technology, video encoding and decoding, video transmiss-ion, multi-single chip microcomputer communication, dat-abase technology, computer software and robot technology. The robot can adaptively adjust its status according to diameter (from 400 mm to 650 mm) of pipeline. The maximum detection distance is up to 1 000 m. The method of video coding in the system is based on fractal transformation. The experiments show that the coding scheme is fast and good PSNR. The precision of on-line detection is up to 3% thickness of pipeline wall. The robot can also have a high precision of location up to 0.03 m. The control method is based on network and characterized by on-line and real-time. The experiment in real gas pipeline shows that the performance of the detection system is good.展开更多
Globally, traditional power systems are rapidly transforming towards the adoption of smart grid platforms. Substations which are at the center of the electric power transformation from the power plant are changing to ...Globally, traditional power systems are rapidly transforming towards the adoption of smart grid platforms. Substations which are at the center of the electric power transformation from the power plant are changing to IEC 61850 based digital substations. Therefore, within substation, there is a growing demand for the IEC 61850 based Intelligent Electronic Devices (IEDs). The operation of multiple manufacturers of IEDs in a single digital substation network increases the need for IEC 61850 communications specification conformance diagnosis to ensure interoperability for efficient data exchange between IEDs. The IEC 61850-10 presents test items for diagnosing communication specification conformance. There are many test tools available in the market today to test the compliance of the IEC 61850 communications specifications to the IED. In this paper, we propose a model-based diagnostic method for IED communication conformance testing. The proposed model-based software therefore uses the “drag and drop” technique to select the various IEC 61850 communication services (objects) required to design the test case in a user friendly Graphical User Interface (GUI). This makes the service conformance testing more flexible for test engineers and system integrators especially in situations that require test case modifications. Also, the proposed software tool makes it easy to understand the various IEC 61850 services using the friendly GUI.展开更多
The frequent attacks on network infrastructure, using various forms of denial of service attacks, have led to an increased need for developing new techniques for analyzing network traffic. If efficient analysis tools ...The frequent attacks on network infrastructure, using various forms of denial of service attacks, have led to an increased need for developing new techniques for analyzing network traffic. If efficient analysis tools were available, it could become possible to detect the attacks and to take action to weaken those attacks appropriately before they have had time to propagate across the network. In this paper, we propose an SNMP MIB oriented approach for detecting attacks, which is based on two-tier GCT by analyzing causal relationship between attacking variable at the attacker and abnormal variable at the target. According to the abnormal behavior at the target, GCT is executed initially to determine preliminary attacking variable, which has whole causality with abnormal variable in network behavior. Depending on behavior feature extracted from abnormal behavior, we can recognize attacking variable by using GCT again, which has local causality with abnormal variable in local behavior. Proactive detecting rules can be constructed with the causality between attacking variable and abnormal variable, which can be used to give alarms in network management system. The results of experiment showed that the approach with two-tier GCT was proved to detect attacks early, with which attack propagation could be slowed through early detection.展开更多
1553B avionics data bus network may fail due to vibration,temperature,humidity or human error.Therefore,the research on detection technology of 1553B avionics data bus network is an important subject.The key technolog...1553B avionics data bus network may fail due to vibration,temperature,humidity or human error.Therefore,the research on detection technology of 1553B avionics data bus network is an important subject.The key technologies are studied by analyzing the possible faults of the network,including four-wire DC resistance measurement method for conductors-to-shield short test and stub continuity test,equivalent impedance measurement of coupling transformer for main bus continuity test,polarity reversal test base on duty ratio measurement,attenuation measurement base on coupler model,and data path integrity test base on bit error rate calculation.Finally,the implementation methods of key technologies are researched,a portable integrated automatic test system of 1553B data bus network is constructed based on PC 104 computer,and the hardware configuration and test process are especially designed.展开更多
Introduction:To evaluate the efficiency and effectiveness of Volunteer-Based Social Network human immunodeficiency virus(HIV)Testing Services(VBSNS).Methods:Collaborating with a local nongovernmental organization,we r...Introduction:To evaluate the efficiency and effectiveness of Volunteer-Based Social Network human immunodeficiency virus(HIV)Testing Services(VBSNS).Methods:Collaborating with a local nongovernmental organization,we recruited eligible elderly men who have sex with men(MSM)between 2021 and 2024.Participants were assigned to either the traditional Community-Based HIV Testing Services(CBHTS)group or the VBSNS group.We conducted questionnaire surveys,HIV and syphilis antibody rapid testing.Results:We recruited 144 volunteers,each of whom facilitated HIV testing for 9.13 participants on average.VBSNS accounted for 47.9%of all HIV tests and covered 66.6%of suburban areas.It also accounted for 67.2%of all newly reported cases,compared to only 32.8%for CBHTS.A higher proportion of testers who were under age 60,single,married,or cohabiting,with an education level of below junior college participated in VBSNS.Conversely,a smaller proportion of VBSNS participants reported identifying as homosexual,practiced HIV prevention measures beyond condom use,and had received HIV testing.Conclusions:VBSNS effectively increased HIV testing uptake and new case identification among MSM in remote areas,successfully reaching a high-risk population.This model provides a valuable alternative for settings where traditional methods such as on-site testing and counseling are inaccessible.展开更多
To improve the efficiency and coverage of stateful network protocol fuzzing, this paper proposes a new method, using a rule-based state machine and a stateful rule tree to guide the generation of fuzz testing data. Th...To improve the efficiency and coverage of stateful network protocol fuzzing, this paper proposes a new method, using a rule-based state machine and a stateful rule tree to guide the generation of fuzz testing data. The method first builds a rule-based state machine model as a formal description of the states of a network protocol. This removes safety paths, to cut down the scale of the state space. Then it uses a stateful rule tree to describe the relationship between states and messages, and then remove useless items from it. According to the message sequence obtained by the analysis of paths using the stateful rule tree and the protocol specification, an abstract data model of test case generation is defined. The fuzz testing data is produced by various generation algorithms through filling data in the fields of the data model. Using the rule-based state machine and the stateful rule tree, the quantity of test data can be reduced. Experimental results indicate that our method can discover the same vulnerabilities as traditional approaches, using less test data, while optimizing test data generation and improving test efficiency.展开更多
基金Supported by the National Science and Technology Major Project(2017ZX05009005-002)
文摘An automatic well test interpretation method for radial composite reservoirs based on convolutional neural network(CNN) is proposed, and its effectiveness and accuracy are verified by actual field data. In this paper, based on the data transformed by logarithm function and the loss function of mean square error(MSE), the optimal CNN is obtained by reducing the loss function to optimize the network with "dropout" method to avoid over fitting. The trained optimal network can be directly used to interpret the buildup or drawdown pressure data of the well in the radial composite reservoir, that is, the log-log plot of the given measured pressure variation and its derivative data are input into the network, the outputs are corresponding reservoir parameters(mobility ratio, storativity ratio, dimensionless composite radius, and dimensionless group characterizing well storage and skin effects), which realizes the automatic initial fitting of well test interpretation parameters. The method is verified with field measured data of Daqing Oilfield. The research shows that the method has high interpretation accuracy, and it is superior to the analytical method and the least square method.
文摘Unified modeling language （UML） is a powerful graphical modeling language with intuitional meaning. It provides various diagrams to depict system characteristics and complex environment from different viewpoints and different application layers. UML-based software development and modeling environments have been widely accepted in industry, including areas in which safety is an important issue such as spaceflight, defense, automobile, etc. To ensure and improve software quality becomes a main concern in the field. As one of the key techniques for software quality, software testing can effectively detect system faults. UML based software testing based is an important research direction in software engineering. The key to software testing is the generation of test cases. This dissertation studies an approach to generating test cases from UML statecharts.
基金Supported by the National High technology Research and Development Program of China (No.2002 AA442110)
文摘The detection system integrates control technology, network technology, video encoding and decoding, video transmiss-ion, multi-single chip microcomputer communication, dat-abase technology, computer software and robot technology. The robot can adaptively adjust its status according to diameter (from 400 mm to 650 mm) of pipeline. The maximum detection distance is up to 1 000 m. The method of video coding in the system is based on fractal transformation. The experiments show that the coding scheme is fast and good PSNR. The precision of on-line detection is up to 3% thickness of pipeline wall. The robot can also have a high precision of location up to 0.03 m. The control method is based on network and characterized by on-line and real-time. The experiment in real gas pipeline shows that the performance of the detection system is good.
文摘Globally, traditional power systems are rapidly transforming towards the adoption of smart grid platforms. Substations which are at the center of the electric power transformation from the power plant are changing to IEC 61850 based digital substations. Therefore, within substation, there is a growing demand for the IEC 61850 based Intelligent Electronic Devices (IEDs). The operation of multiple manufacturers of IEDs in a single digital substation network increases the need for IEC 61850 communications specification conformance diagnosis to ensure interoperability for efficient data exchange between IEDs. The IEC 61850-10 presents test items for diagnosing communication specification conformance. There are many test tools available in the market today to test the compliance of the IEC 61850 communications specifications to the IED. In this paper, we propose a model-based diagnostic method for IED communication conformance testing. The proposed model-based software therefore uses the “drag and drop” technique to select the various IEC 61850 communication services (objects) required to design the test case in a user friendly Graphical User Interface (GUI). This makes the service conformance testing more flexible for test engineers and system integrators especially in situations that require test case modifications. Also, the proposed software tool makes it easy to understand the various IEC 61850 services using the friendly GUI.
文摘The frequent attacks on network infrastructure, using various forms of denial of service attacks, have led to an increased need for developing new techniques for analyzing network traffic. If efficient analysis tools were available, it could become possible to detect the attacks and to take action to weaken those attacks appropriately before they have had time to propagate across the network. In this paper, we propose an SNMP MIB oriented approach for detecting attacks, which is based on two-tier GCT by analyzing causal relationship between attacking variable at the attacker and abnormal variable at the target. According to the abnormal behavior at the target, GCT is executed initially to determine preliminary attacking variable, which has whole causality with abnormal variable in network behavior. Depending on behavior feature extracted from abnormal behavior, we can recognize attacking variable by using GCT again, which has local causality with abnormal variable in local behavior. Proactive detecting rules can be constructed with the causality between attacking variable and abnormal variable, which can be used to give alarms in network management system. The results of experiment showed that the approach with two-tier GCT was proved to detect attacks early, with which attack propagation could be slowed through early detection.
基金supported by the Key Equipment Research Project of Air Force of China(KJ2011215)
文摘1553B avionics data bus network may fail due to vibration,temperature,humidity or human error.Therefore,the research on detection technology of 1553B avionics data bus network is an important subject.The key technologies are studied by analyzing the possible faults of the network,including four-wire DC resistance measurement method for conductors-to-shield short test and stub continuity test,equivalent impedance measurement of coupling transformer for main bus continuity test,polarity reversal test base on duty ratio measurement,attenuation measurement base on coupler model,and data path integrity test base on bit error rate calculation.Finally,the implementation methods of key technologies are researched,a portable integrated automatic test system of 1553B data bus network is constructed based on PC 104 computer,and the hardware configuration and test process are especially designed.
基金Supported by the National Natural Science Foundation of China(Grant No.72374153)Tianjin Health Research Project(Grant No.TJWJ2023QN092)Public Health Professionals Promotion Project.
文摘Introduction:To evaluate the efficiency and effectiveness of Volunteer-Based Social Network human immunodeficiency virus(HIV)Testing Services(VBSNS).Methods:Collaborating with a local nongovernmental organization,we recruited eligible elderly men who have sex with men(MSM)between 2021 and 2024.Participants were assigned to either the traditional Community-Based HIV Testing Services(CBHTS)group or the VBSNS group.We conducted questionnaire surveys,HIV and syphilis antibody rapid testing.Results:We recruited 144 volunteers,each of whom facilitated HIV testing for 9.13 participants on average.VBSNS accounted for 47.9%of all HIV tests and covered 66.6%of suburban areas.It also accounted for 67.2%of all newly reported cases,compared to only 32.8%for CBHTS.A higher proportion of testers who were under age 60,single,married,or cohabiting,with an education level of below junior college participated in VBSNS.Conversely,a smaller proportion of VBSNS participants reported identifying as homosexual,practiced HIV prevention measures beyond condom use,and had received HIV testing.Conclusions:VBSNS effectively increased HIV testing uptake and new case identification among MSM in remote areas,successfully reaching a high-risk population.This model provides a valuable alternative for settings where traditional methods such as on-site testing and counseling are inaccessible.
基金supported by the Key Project of National Defense Basic Research Program of China (No.B1120132031)supported by the Cultivation and Development Program for Technology Innovation Base of Beijing Municipal Science and Technology Commission (No.Z151100001615034)
文摘To improve the efficiency and coverage of stateful network protocol fuzzing, this paper proposes a new method, using a rule-based state machine and a stateful rule tree to guide the generation of fuzz testing data. The method first builds a rule-based state machine model as a formal description of the states of a network protocol. This removes safety paths, to cut down the scale of the state space. Then it uses a stateful rule tree to describe the relationship between states and messages, and then remove useless items from it. According to the message sequence obtained by the analysis of paths using the stateful rule tree and the protocol specification, an abstract data model of test case generation is defined. The fuzz testing data is produced by various generation algorithms through filling data in the fields of the data model. Using the rule-based state machine and the stateful rule tree, the quantity of test data can be reduced. Experimental results indicate that our method can discover the same vulnerabilities as traditional approaches, using less test data, while optimizing test data generation and improving test efficiency.
