EMulate Therapeutics has developed a system for emulating the effects of solvated molecules via their magnetic field recordings. Recordings of magnetic field emissions of select small inhibitor RNAs (siRNAs;murine tar...EMulate Therapeutics has developed a system for emulating the effects of solvated molecules via their magnetic field recordings. Recordings of magnetic field emissions of select small inhibitor RNAs (siRNAs;murine targeting CTLA-4 and murine targeting PD-1) were tested on C57Bl/6 mice implanted subcutaneously with the GL261 murine tumor cell line. A signal composed of concatenated recordings of siRNA molecules targeting the murine CTLA-4 and PD-1 receptors (labeled A2) was used in immune competent C57Bl/6 mice. The mice were flank implanted with the murine glioblastoma cell line GL261. Mice were exposed to the signal continuously (24 hours a day) until tumor volumes reached the designated volume limit. Tumors were excised and analyzed via PAGE/Western blot for the expression of CTLA-4, PD-1, Ki67, Caspase 3, CD4 and CD8. Terminal blood draws were used for CBCs. We report the down regulation of the checkpoint inhibitors CTLA-4 in the exposed mice. Significant tumor volume reduction was observed in mice exposed to the siRNA signal compared to control mice;no adverse events were recorded. Cell blood counts (CBC) and protein expression patterns were observed to correlate with the expected function of protein expression inhibition of the targets.展开更多
A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an act...A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an actual ship parameter and its accurate propeller J＇ -KT＇ and J＇ - Kp＇ curve data, functional experiments based on the simulation system were carried out. The experiment results showed that the system can correctly emulate the propeller characteristics, produce the dynamic and steady performances of the propeller under different navigation modes, and present actual load torque for electric propulsion motor.展开更多
The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inerti...The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and uncertainties.To reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia emulation.The inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary.By well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be reduced.The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements.Simulation studies demonstrate the effectiveness of the proposed solution.展开更多
Traffic monitoring is of major importance for enforcing traffic management policies.To accomplish this task,the detection of vehicle can be achieved by exploiting image analysis techniques.In this paper,a solution is ...Traffic monitoring is of major importance for enforcing traffic management policies.To accomplish this task,the detection of vehicle can be achieved by exploiting image analysis techniques.In this paper,a solution is presented to obtain various traffic parameters through vehicular video detection system(VVDS).VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time.This algorithm uses the background differencing method,and vehicles can be detected through luminance difference of pixels between background image and current image.Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy.Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process four-channel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP′s high performance.In the end,VVDS is tested on real-world scenes and experiment results show that the system is both fast and robust to the surveillance of transportation.展开更多
The ambitious global targets on decarbonization present the need for massive integration of renewable generation in power systems,resulting in a significant decrease in the system inertia.In addition to the reduction ...The ambitious global targets on decarbonization present the need for massive integration of renewable generation in power systems,resulting in a significant decrease in the system inertia.In addition to the reduction in system inertia,the transmission system in Great Britain(GB)faces some unique challenges owing to its relatively small capacity,while being decoupled from other transmission systems and with the renewable resources largely non-uniformly distributed across the system.This paper presents opinions and insights on the challenges associated with frequency control in a low-inertia system and the potential solutions from a GB perspective.In this paper,we focus on three main techniques that act over different time scales:synchronous condensers,inertia emulation,and fast frequency response.We evaluate their relative advantages and limitations with learnings from recent research and development projects in GB,along with the opinions on their roles in addressing the frequency control challenges in future low-inertia systems.展开更多
Ferroresonance is a complex nonlinear electrotechnical phenomenon, which can result in thermal and electrical stresses on the electric power system equipments due to the over voltages and over currents it generates. T...Ferroresonance is a complex nonlinear electrotechnical phenomenon, which can result in thermal and electrical stresses on the electric power system equipments due to the over voltages and over currents it generates. The prediction or determination of ferroresonance depends mainly on the accuracy of the model used. Fractional-order models are more accurate than the integer-order models. In this paper, a fractional-order ferroresonance model is proposed. The influence of the order on the dynamic behaviors of this fractional-order system under different parameters n and F is investigated. Compared with the integral-order ferroresonance system, small change of the order not only affects the dynamic behavior of the system, but also significantly affects the harmonic components of the system. Then the fractional-order ferroresonance system is implemented by nonlinear circuit emulator. Finally, a fractional-order adaptive sliding mode control （FASMC） method is used to eliminate the abnormal operation state of power system. Since the introduction of the fractional-order sliding mode surface and the adaptive factor, the robustness and disturbance rejection of the controlled system are en- hanced. Numerical simulation results demonstrate that the proposed FASMC controller works well for suppression of ferroresonance over voltage.展开更多
The Loess Plateau, covered with thick loess, lies in the middle reaches of the YellowRiver to the west of the Taihangshan Mountains, east of the Wuqiao Mountains south ofYinshan Mountains and north of the Qinling Moun...The Loess Plateau, covered with thick loess, lies in the middle reaches of the YellowRiver to the west of the Taihangshan Mountains, east of the Wuqiao Mountains south ofYinshan Mountains and north of the Qinling Mountains with a total area of 56×10~4km^2.The plateau is 1000--2500m above sea level and has loess as thick as 100--200 metres, be-展开更多
Objective Network emulation system constructs a virtual network environment which has the characteristics of controllable and repeatable network conditions. This makes it possible to predict the availability and perfo...Objective Network emulation system constructs a virtual network environment which has the characteristics of controllable and repeatable network conditions. This makes it possible to predict the availability and performance of new protocols and algorithms before deploying to Internet. Methods PARNEM, a parallel discrete event network emulation system described in this paper has the following characteristics: ① BREEN - a BSP based real-time event scheduling engine; ② application transparent flexible interactive mechanism; ③ legacy network model reuse. Conclusion PARNEM allows detailed and accurate study of application behavior. Comprehensive case studies covering bottleneck bandwidth measurement and distributed cooperative web caching system demonstrate that network emulation technology opens a wide range of new opportunities for examining the behavior of applications.展开更多
Emulation platforms are critical for evaluation and verification in the research of networking technologies and protocols for space networks(SN).High fidelity emulating technologies have been extensively studied for S...Emulation platforms are critical for evaluation and verification in the research of networking technologies and protocols for space networks(SN).High fidelity emulating technologies have been extensively studied for SN in earlier work,while little emphasis has been placed on the performance evaluation part.In this paper,the design of a network performance analysis architecture is presented,with which high-speed network traffic can be captured and indexed,and the performance of the emulated SN can be well analyzed and evaluated.This architecture comprises three components,namely capture layer,storage layer and analysis layer.Analytic Hierarchy Process(AHP)and several analysis methods are adopted to evaluate the network performance comprehensively.In the implementation of the proposed architecture,configuration optimization and parallel processing are applied to handle large amount of high-speed network traffic.Finally,experiment results through the analysis system exhibits the effectiveness of the proposed architecture.展开更多
This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based auto...This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based autonomous power systems in a laboratory environment where the operation of a real diesel generator is not possible. The emulator basically consists in a voltage source inverter with a second order output filter which voltage references are given by the model of the diesel generator. The control of the emulator is based on the digital signal processor TMS320F2812, where the mathematical models of the diesel generator and the control of the inverter are computed in real-time. Parameters for the model were obtained from commercially available components. Experimental results for different values of speed droop showed that the emulator achieves a satisfactory performance in the transient and stationary response. For the stationary response, the measured frequency deviates from theoretical values with a mean absolute error of: 0.06 Hz for 0% droop, 0.037 Hz for 3% droop, and 0.087 Hz for 5% droop. For the transient response, the measured frequency nadir deviates from simulations in: 0.05 Hz for 0% droop, 0.02 Hz for 3% droop, and 0.1 Hz for 5% droop.展开更多
Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall...Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall face was emulated, in which the methods of time pace and computer random emulation were adopted. The paper provides an objective basis for the analysis of a mining Iongwall face and the varied lines of effectiveness, machine stoppage rate and coal flow of components and system, and output etc.lt also offers some theories to improve productivity by discussing the application of the transformation plan and optimization of reasonable coal stock capacity, as well as selection of system equipment and matching optimization.展开更多
A real-time workbench able to reproduce the same behavior as an indoor network is in order. Such a tool will help researchers and industrials extend the smart grid technology indoors and have a better acknowledgment o...A real-time workbench able to reproduce the same behavior as an indoor network is in order. Such a tool will help researchers and industrials extend the smart grid technology indoors and have a better acknowledgment of Smart Grid systems interoperability. In order to develop such a tool many approaches should be studied to choose the most suitable one by comparing the models and the technologies. The considered hardware are the embedded systems and the selected approach is the statistical one. It appears that the FlR filter is the most pertinent approach.展开更多
Internet of things (IoT) devices make up 30%of all network-connected endpoints,introducing vulnerabilities and novel attacks that make many companies as primary targets for cybercriminals.To address this increasing th...Internet of things (IoT) devices make up 30%of all network-connected endpoints,introducing vulnerabilities and novel attacks that make many companies as primary targets for cybercriminals.To address this increasing threat surface,every organization deploying IoT devices needs to consider security risks to ensure those devices are secure and trusted.Among all the solutions for security risks,firmware security analysis is essential to fix software bugs,patch vulnerabilities,or add new security features to protect users of those vulnerable devices.However,firmware security analysis has never been an easy job due to the diversity of the execution environment and the close source of firmware.These two distinct features complicate the operations to unpack firmware samples for detailed analysis.They also make it difficult to create visual environments to emulate the running of device firmware.Although researchers have developed many novel methods to overcome various challenges in the past decade,critical barriers impede firmware security analysis in practice.Therefore,this survey is motivated to systematically review and analyze the research challenges and their solutions,considering both breadth and depth.Specifically,based on the analysis perspectives,various methods that perform security analysis on IoT devices are introduced and classified into four categories.The challenges in each category are discussed in detail,and potential solutions are proposed subsequently.We then discuss the flaws of these solutions and provide future directions for this research field.This survey can be utilized by a broad range of readers,including software developers,cyber security researchers,and software security engineers,to better understand firmware security analysis.展开更多
In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at b...In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel environment.For the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational complexity.On the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading environment.Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods.The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms.Furthermore,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization.Moreover,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active probes.The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.展开更多
Internet of things(IoT)devices are being increasingly used in numerous areas.However,the low priority on security and various IoT types have made these devices vulnerable to attacks.To prevent this,recent studies have...Internet of things(IoT)devices are being increasingly used in numerous areas.However,the low priority on security and various IoT types have made these devices vulnerable to attacks.To prevent this,recent studies have analyzed firmware in an emulation environment that does not require actual devices and is efficient for repeated experiments.However,these studies focused only on major firmware architectures and rarely considered exotic firmware.In addition,because of the diversity of firmware,the emulation success rate is not high in terms of large-scale analyses.In this study,we propose the adaptive emulation framework for multi-architecture(AEMA).In the field of automated emulation frameworks for IoT firmware testing,AEMA considers the following issues:(1)limited compatibility for exotic firmware architectures,(2)emulation instability when configuring an automated environment,and(3)shallow testing range resulting from structured inputs.To tackle these problems,AEMAcan emulate not onlymajor firmware architectures but also exotic firmware architectures not previously considered,such as Xtensa,ColdFire,and reduced instruction set computer(RISC)version five,by implementing a minority emulator.Moreover,we applied the emulation arbitration technique and input keyword extraction technique for emulation stability and efficient test case generation.We compared AEMA with other existing frameworks in terms of emulation success rates and fuzz testing.As a result,AEMA succeeded in emulating 864 out of 1,083 overall experimental firmware and detected vulnerabilities at least twice as fast as the experimental group.Furthermore,AEMAfound a 0-day vulnerability in realworld IoT devices within 24 h.展开更多
文摘EMulate Therapeutics has developed a system for emulating the effects of solvated molecules via their magnetic field recordings. Recordings of magnetic field emissions of select small inhibitor RNAs (siRNAs;murine targeting CTLA-4 and murine targeting PD-1) were tested on C57Bl/6 mice implanted subcutaneously with the GL261 murine tumor cell line. A signal composed of concatenated recordings of siRNA molecules targeting the murine CTLA-4 and PD-1 receptors (labeled A2) was used in immune competent C57Bl/6 mice. The mice were flank implanted with the murine glioblastoma cell line GL261. Mice were exposed to the signal continuously (24 hours a day) until tumor volumes reached the designated volume limit. Tumors were excised and analyzed via PAGE/Western blot for the expression of CTLA-4, PD-1, Ki67, Caspase 3, CD4 and CD8. Terminal blood draws were used for CBCs. We report the down regulation of the checkpoint inhibitors CTLA-4 in the exposed mice. Significant tumor volume reduction was observed in mice exposed to the siRNA signal compared to control mice;no adverse events were recorded. Cell blood counts (CBC) and protein expression patterns were observed to correlate with the expected function of protein expression inhibition of the targets.
基金supported by the Fund of Shanghai Committee of Science and Technology(Grant No.11170501700)the International Cooperation and Exchange Projects of the Ministry of Science and Technology(Grant No.2012DFG71850)
文摘A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an actual ship parameter and its accurate propeller J＇ -KT＇ and J＇ - Kp＇ curve data, functional experiments based on the simulation system were carried out. The experiment results showed that the system can correctly emulate the propeller characteristics, produce the dynamic and steady performances of the propeller under different navigation modes, and present actual load torque for electric propulsion motor.
文摘The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and uncertainties.To reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia emulation.The inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary.By well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be reduced.The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements.Simulation studies demonstrate the effectiveness of the proposed solution.
文摘Traffic monitoring is of major importance for enforcing traffic management policies.To accomplish this task,the detection of vehicle can be achieved by exploiting image analysis techniques.In this paper,a solution is presented to obtain various traffic parameters through vehicular video detection system(VVDS).VVDS exploits the algorithm based on virtual loops to detect moving vehicle in real time.This algorithm uses the background differencing method,and vehicles can be detected through luminance difference of pixels between background image and current image.Furthermore a novel technology named as spatio-temporal image sequences analysis is applied to background differencing to improve detection accuracy.Then a hardware implementation of a digital signal processing (DSP) based board is described in detail and the board can simultaneously process four-channel video from different cameras. The benefit of usage of DSP is that images of a roadway can be processed at frame rate due to DSP′s high performance.In the end,VVDS is tested on real-world scenes and experiment results show that the system is both fast and robust to the surveillance of transportation.
文摘The ambitious global targets on decarbonization present the need for massive integration of renewable generation in power systems,resulting in a significant decrease in the system inertia.In addition to the reduction in system inertia,the transmission system in Great Britain(GB)faces some unique challenges owing to its relatively small capacity,while being decoupled from other transmission systems and with the renewable resources largely non-uniformly distributed across the system.This paper presents opinions and insights on the challenges associated with frequency control in a low-inertia system and the potential solutions from a GB perspective.In this paper,we focus on three main techniques that act over different time scales:synchronous condensers,inertia emulation,and fast frequency response.We evaluate their relative advantages and limitations with learnings from recent research and development projects in GB,along with the opinions on their roles in addressing the frequency control challenges in future low-inertia systems.
基金supported by the National Natural Science Foundation of China(Grant No.51507134)the Science Fund from the Education Department of Shaanxi Province,China(Grant No.15JK1537)
文摘Ferroresonance is a complex nonlinear electrotechnical phenomenon, which can result in thermal and electrical stresses on the electric power system equipments due to the over voltages and over currents it generates. The prediction or determination of ferroresonance depends mainly on the accuracy of the model used. Fractional-order models are more accurate than the integer-order models. In this paper, a fractional-order ferroresonance model is proposed. The influence of the order on the dynamic behaviors of this fractional-order system under different parameters n and F is investigated. Compared with the integral-order ferroresonance system, small change of the order not only affects the dynamic behavior of the system, but also significantly affects the harmonic components of the system. Then the fractional-order ferroresonance system is implemented by nonlinear circuit emulator. Finally, a fractional-order adaptive sliding mode control （FASMC） method is used to eliminate the abnormal operation state of power system. Since the introduction of the fractional-order sliding mode surface and the adaptive factor, the robustness and disturbance rejection of the controlled system are en- hanced. Numerical simulation results demonstrate that the proposed FASMC controller works well for suppression of ferroresonance over voltage.
文摘The Loess Plateau, covered with thick loess, lies in the middle reaches of the YellowRiver to the west of the Taihangshan Mountains, east of the Wuqiao Mountains south ofYinshan Mountains and north of the Qinling Mountains with a total area of 56×10~4km^2.The plateau is 1000--2500m above sea level and has loess as thick as 100--200 metres, be-
基金This work was supported by the National Natural Science Foundation Major Programof China (No.90412011) .
文摘Objective Network emulation system constructs a virtual network environment which has the characteristics of controllable and repeatable network conditions. This makes it possible to predict the availability and performance of new protocols and algorithms before deploying to Internet. Methods PARNEM, a parallel discrete event network emulation system described in this paper has the following characteristics: ① BREEN - a BSP based real-time event scheduling engine; ② application transparent flexible interactive mechanism; ③ legacy network model reuse. Conclusion PARNEM allows detailed and accurate study of application behavior. Comprehensive case studies covering bottleneck bandwidth measurement and distributed cooperative web caching system demonstrate that network emulation technology opens a wide range of new opportunities for examining the behavior of applications.
基金supported by the National Natural Science Foundation of China under Grant 62131012the Fundamental Research Funds for the Central Universities under Grant 021014380187。
文摘Emulation platforms are critical for evaluation and verification in the research of networking technologies and protocols for space networks(SN).High fidelity emulating technologies have been extensively studied for SN in earlier work,while little emphasis has been placed on the performance evaluation part.In this paper,the design of a network performance analysis architecture is presented,with which high-speed network traffic can be captured and indexed,and the performance of the emulated SN can be well analyzed and evaluated.This architecture comprises three components,namely capture layer,storage layer and analysis layer.Analytic Hierarchy Process(AHP)and several analysis methods are adopted to evaluate the network performance comprehensively.In the implementation of the proposed architecture,configuration optimization and parallel processing are applied to handle large amount of high-speed network traffic.Finally,experiment results through the analysis system exhibits the effectiveness of the proposed architecture.
文摘This paper presents the modeling, simulation and practical implementation of an inverter-based diesel generator emulator. The main purpose of this emulator is for the study of frequency variations in diesel-based autonomous power systems in a laboratory environment where the operation of a real diesel generator is not possible. The emulator basically consists in a voltage source inverter with a second order output filter which voltage references are given by the model of the diesel generator. The control of the emulator is based on the digital signal processor TMS320F2812, where the mathematical models of the diesel generator and the control of the inverter are computed in real-time. Parameters for the model were obtained from commercially available components. Experimental results for different values of speed droop showed that the emulator achieves a satisfactory performance in the transient and stationary response. For the stationary response, the measured frequency deviates from theoretical values with a mean absolute error of: 0.06 Hz for 0% droop, 0.037 Hz for 3% droop, and 0.087 Hz for 5% droop. For the transient response, the measured frequency nadir deviates from simulations in: 0.05 Hz for 0% droop, 0.02 Hz for 3% droop, and 0.1 Hz for 5% droop.
基金Supported by the Special Topics of Major Scientific and Technological Research Projects Shanxi Province (2006031099-01)Youth Science Funds of Shanxi Province (2006021024)Science and Technology Project of Taiyuan City (07010728)
文摘Based on the theory of random process and the characteristic of the functioning of a system component subject to a certain specific probability distribution, emulated the whole process of system production on Iongwall face was emulated, in which the methods of time pace and computer random emulation were adopted. The paper provides an objective basis for the analysis of a mining Iongwall face and the varied lines of effectiveness, machine stoppage rate and coal flow of components and system, and output etc.lt also offers some theories to improve productivity by discussing the application of the transformation plan and optimization of reasonable coal stock capacity, as well as selection of system equipment and matching optimization.
文摘A real-time workbench able to reproduce the same behavior as an indoor network is in order. Such a tool will help researchers and industrials extend the smart grid technology indoors and have a better acknowledgment of Smart Grid systems interoperability. In order to develop such a tool many approaches should be studied to choose the most suitable one by comparing the models and the technologies. The considered hardware are the embedded systems and the selected approach is the statistical one. It appears that the FlR filter is the most pertinent approach.
文摘Internet of things (IoT) devices make up 30%of all network-connected endpoints,introducing vulnerabilities and novel attacks that make many companies as primary targets for cybercriminals.To address this increasing threat surface,every organization deploying IoT devices needs to consider security risks to ensure those devices are secure and trusted.Among all the solutions for security risks,firmware security analysis is essential to fix software bugs,patch vulnerabilities,or add new security features to protect users of those vulnerable devices.However,firmware security analysis has never been an easy job due to the diversity of the execution environment and the close source of firmware.These two distinct features complicate the operations to unpack firmware samples for detailed analysis.They also make it difficult to create visual environments to emulate the running of device firmware.Although researchers have developed many novel methods to overcome various challenges in the past decade,critical barriers impede firmware security analysis in practice.Therefore,this survey is motivated to systematically review and analyze the research challenges and their solutions,considering both breadth and depth.Specifically,based on the analysis perspectives,various methods that perform security analysis on IoT devices are introduced and classified into four categories.The challenges in each category are discussed in detail,and potential solutions are proposed subsequently.We then discuss the flaws of these solutions and provide future directions for this research field.This survey can be utilized by a broad range of readers,including software developers,cyber security researchers,and software security engineers,to better understand firmware security analysis.
基金supported by National Natural Science Foundation of China(No.62090015,No.61821001)BUPT Excellent Ph.D.Students Foundation under Grant(CX2021216)。
文摘In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel environment.For the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational complexity.On the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading environment.Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods.The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms.Furthermore,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization.Moreover,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active probes.The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.
基金This work was supported by the Ministry of Science and ICT(MSIT)Korea,under the Information Technology Research Center(ITRC)support program(IITP-2022-2018-0-01423)+2 种基金supervised by the Institute for Information&Communications Technology Planning&Evaluation(IITP)by MSIT,Korea under the ITRC support program(IITP-2021-2020-0-01602)supervised by the IITP.
文摘Internet of things(IoT)devices are being increasingly used in numerous areas.However,the low priority on security and various IoT types have made these devices vulnerable to attacks.To prevent this,recent studies have analyzed firmware in an emulation environment that does not require actual devices and is efficient for repeated experiments.However,these studies focused only on major firmware architectures and rarely considered exotic firmware.In addition,because of the diversity of firmware,the emulation success rate is not high in terms of large-scale analyses.In this study,we propose the adaptive emulation framework for multi-architecture(AEMA).In the field of automated emulation frameworks for IoT firmware testing,AEMA considers the following issues:(1)limited compatibility for exotic firmware architectures,(2)emulation instability when configuring an automated environment,and(3)shallow testing range resulting from structured inputs.To tackle these problems,AEMAcan emulate not onlymajor firmware architectures but also exotic firmware architectures not previously considered,such as Xtensa,ColdFire,and reduced instruction set computer(RISC)version five,by implementing a minority emulator.Moreover,we applied the emulation arbitration technique and input keyword extraction technique for emulation stability and efficient test case generation.We compared AEMA with other existing frameworks in terms of emulation success rates and fuzz testing.As a result,AEMA succeeded in emulating 864 out of 1,083 overall experimental firmware and detected vulnerabilities at least twice as fast as the experimental group.Furthermore,AEMAfound a 0-day vulnerability in realworld IoT devices within 24 h.
