The forthcoming European Higher Education Area has implied an important change in the teaching/learning process:it is necessary to get students more involved as well as to promote their independence and active partici...The forthcoming European Higher Education Area has implied an important change in the teaching/learning process:it is necessary to get students more involved as well as to promote their independence and active participation.Furthermore,Information and Communication Technology is progressively including greater spaces in human beings’life,as economics,arts,engineering and education,among others fields.Therefore,a web tool,based on a content management system,has been developed to teach the Power Electronics subject.Moreover,the use of these multimedia tools makes it possible to encourage students’independence.This developed educational software is necessary as an important resource in the students’teaching/learning process.Therefore,the importance of evaluation models increases in as much as the application of these instruments allows its effective evaluation.It offers a greater guarantee of its use in these environments from the students’point of view.An evaluation process,by means of several surveys for students and lecturers,is used in order to evaluate the quality of these multimedia interactive tools.The results demonstrate that the use of this web tool increases students’motivation significantly.展开更多
Electric Vehicle (EV) adoption is rapidly increasing, necessitating efficient and precise methods for predicting EV charging requirements. The early and precise prediction of the battery discharging status is helpful ...Electric Vehicle (EV) adoption is rapidly increasing, necessitating efficient and precise methods for predicting EV charging requirements. The early and precise prediction of the battery discharging status is helpful to avoid the complete discharging of the battery. The complete discharge of the battery degrades its lifetime and requires a longer charging duration. In the present work, a novel approach leverages the Edge Impulse platform for live prediction of the battery status and early alert signal to avoid complete discharging. The proposed method predicts the actual remaining useful life of batteries. A powerful edge computing platform utilizes Tensor Flow-based machine learning models to predict EV charging needs accurately. The proposed method improves the overall lifetime of the battery by the efficient utilization and precise prediction of the battery status. The EON-Tuner and DSP processing blocks are used for efficient results. The performance of the proposed method is analyzed in terms of accuracy, mean square error and other performance parameters.展开更多
In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFP) machines, commonly known as “slinky mode” (SM), ob...In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFP) machines, commonly known as “slinky mode” (SM), observed to travel around the torus in Madison Symmetric Torus (MST). The LR analysis is used to utilize the modified Sine-Gordon dynamic equation model to predict with high confidence whether the slinky mode will lock or not lock when compared to the experimentally measured motion of the slinky mode. It is observed that under certain conditions, the slinky mode “locks” at or near the intersection of poloidal and/or toroidal gaps in MST. However, locked mode cease to travel around the torus;while unlocked mode keeps traveling without a change in the energy, making it hard to determine an exact set of conditions to predict locking/unlocking behaviour. The significant key model parameters determined by LR analysis are shown to improve the Sine-Gordon model’s ability to determine the locking/unlocking of magnetohydrodyamic (MHD) modes. The LR analysis of measured variables provides high confidence in anticipating locking versus unlocking of slinky mode proven by relational comparisons between simulations and the experimentally measured motion of the slinky mode in MST.展开更多
In this paper, a combination of model based adaptive design along with adaptive linear output feedback controller is used to compensate for robotic manipulator with output deadzone nonlinearity. The deadzone dynamics ...In this paper, a combination of model based adaptive design along with adaptive linear output feedback controller is used to compensate for robotic manipulator with output deadzone nonlinearity. The deadzone dynamics are utilized to adaptively estimate the deadzone parameter and a switching function is designed to eliminate the error produced in the adaptive observer dynamics. The overall design of the closed loop system ensures stability in the BIBO criterion.展开更多
In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on p...In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators （Cls） are presented, and the optimal Cls set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator （HI） through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor- ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system＇s reliability.展开更多
The mass attenuation coefficients(l/q) for different parts(root, flower, stem, and leaf) of three medicinal aromatic plants(Teucrium chamaedrys L. subsp. sinuatum,Rheum ribes, and Chrysophthalmum montanum) were measur...The mass attenuation coefficients(l/q) for different parts(root, flower, stem, and leaf) of three medicinal aromatic plants(Teucrium chamaedrys L. subsp. sinuatum,Rheum ribes, and Chrysophthalmum montanum) were measured using an ^(241)Am photon source in a stable geometry and calculated using the Monte Carlo N-Particle Transport Code System-extended(MCNPX) code and the WinXCOM program. The experimental and theoretical MCNPX and WinXCOM values exhibited good agreement.The measured mass attenuation coefficient values were then used to compute the effective atomic number(Z_(eff))and electron density(N_E) of the samples. The results reveal that S1-S(stem of Teucrium chamaedrys L. subsp. sinuatum) has the highest values of l/q and Zeff.展开更多
In this study, the gamma radiation shielding features of several environmentally friendly materials were investigated. For this purpose, several attenuation parameters, such as the mass attenuation coefficient (l=q), ...In this study, the gamma radiation shielding features of several environmentally friendly materials were investigated. For this purpose, several attenuation parameters, such as the mass attenuation coefficient (l=q), radiation protection efficiency (RPE), and effective atomic number (Zeff) were determined experimentally and compared with numerical data obtained using WinXCom software. In the measurements, the emitted gamma photons were counted by a gamma spectrometer equipped with an HPGe detector using 22Na, 54Mn, 57Co, 60Co, 133Ba, and 137Cs radioactive point sources in the energy region of 81–1333 keV. The obtained results indicate that the l=q and RPE values of the samples decrease with an increase in photon energy. The experimental values are in good agreement with those obtained using WinXCom software. The RPE and Zeff results show that among the studied materials, the NaY0.77Yb0.20Er0.03F4 sample has the best gamma radiation shielding effectiveness.展开更多
The skin effect in the reversely switched dynistor （RSD） devices is investigated in this paper. Based on the plasma bipolar drift model of the RSD, the current density distributions on the chip are simulated with co...The skin effect in the reversely switched dynistor （RSD） devices is investigated in this paper. Based on the plasma bipolar drift model of the RSD, the current density distributions on the chip are simulated with considering the skin effect. The results indicate that the current density on the border can be several hundred to a thousand A/cm2 higher than that in the center of the chip. The skin effect becomes more prominent as the voltage increases and the inductance decreases in the main circuit. The phenomenon that most of a certain group of chips break over on the border has proved the existence of the skin effect.展开更多
Matrix multiplication plays a pivotal role in the symmetric cipher algorithms, but it is one of the most complex and time consuming units, its performance directly affects the efficiency of cipher algorithms. Combined...Matrix multiplication plays a pivotal role in the symmetric cipher algorithms, but it is one of the most complex and time consuming units, its performance directly affects the efficiency of cipher algorithms. Combined with the characteristics of VLIW processor and matrix multiplication of symmetric cipher algorithms, this paper extracted the reconfigurable elements and analyzed the principle of matrix multiplication, then designed the reconfigurable architecture of matrix multiplication of VLIW processor further, at last we put forward single instructions for matrix multiplication between 4×1 and 4×4 matrix or two 4×4 matrix over GF(2~8), through the instructions extension, the instructions could support larger dimension operations. The experiment shows that the instructions we designed supports different dimensions matrix multiplication and improves the processing speed of multiplication greatly.展开更多
In order to analyze the capacity stability of the time-varying-propagation and delay-dependent of mobile ad-hoc networks （MANETs）, in this paper, a novel approach is proposed to explore the capacity asymptotic stabi...In order to analyze the capacity stability of the time-varying-propagation and delay-dependent of mobile ad-hoc networks （MANETs）, in this paper, a novel approach is proposed to explore the capacity asymptotic stability for the delay- dependent of MANETs based on non-cooperative game theory, where the delay-dependent conditions are explicitly taken into consideration. This approach is based on the Lyapunov-Krasovskii stability theory for functional differential equations and the linear matrix inequality （LMI） technique. A corresponding Lyapunov-Krasovskii functional is introduced for the stability analysis of this system with use of the descriptor and ＂neutral-type＂ model transformation without producing any additional dynamics. The delay-dependent stability criteria are derived for this system. Conditions are given in terms of linear matrix inequalities, and for the first time referred to neutral systems with the time-varying propagation and delay- dependent stability for capacity analysis of MANETs. The proposed criteria are less conservative since they are based on an equivalent model transformation. Furthermore, we also provide an effective and efficient iterative algorithm to solve the constrained stability control model. Simulation experiments have verified the effectiveness and efficiency of our algorithm.展开更多
Free-space optical (FSO) communication requires a line-of-sight connection between a transmitter and a receiver in which the information signal is modulated by an optical carrier that propagates in free space. The FSO...Free-space optical (FSO) communication requires a line-of-sight connection between a transmitter and a receiver in which the information signal is modulated by an optical carrier that propagates in free space. The FSO channel is greatly affected by weather conditions such as fog, rain, and snow. In the literature, several adaptive techniques, such as power control (PC), have been suggested to mitigate channel link degradations. In this paper, we investigate the effects of snow and rain attenuation on the bit error rate (BER) of the FSO system using two types of modulations, the on-off keying (OOK) modulation and the pulse-position modulation (16-PPM). The effect of PC on the performance of FSO communications is also examined in this study. We evaluated the system’s performance with two types of snow, wet snow and dry snow, as well as with different rain regions. Results show that PC improves the BER of the FSO system;a high rate of improvement is found for wet snow and rain. PC has almost no effect with dry snow because of the high attenuation and the limitations on transmitted power. The BER for 16-PPM is better than that for OOK modulation.展开更多
In the driven of big data, social computing and information security is undergoing rapid development and beginning to cross. This paper describes a key-policy attribute-based signcryption scheme which has less computa...In the driven of big data, social computing and information security is undergoing rapid development and beginning to cross. This paper describes a key-policy attribute-based signcryption scheme which has less computation costs than existing similar schemes by utilizing secure outsourcing of scientific computation in cloud computing and eliminates overhead for users, the ciphertext is short, compact, the correctness of transformation algorithm is verifiable. The decrease of ciphertext is 17 %. Additionally, new scheme remits the key escrow problem and is proven selective security in the standard model, it could be verified publicly, applied in mobile devices.展开更多
To solve the problems of data sharing in social network,such as management of private data is too loose,access permissions are not clear,mode of data sharing is too single and soon on,we design a hierarchical access c...To solve the problems of data sharing in social network,such as management of private data is too loose,access permissions are not clear,mode of data sharing is too single and soon on,we design a hierarchical access control scheme of private data based on attribute encryption.First,we construct a new algorithm based on attribute encryption,which divides encryption into two phases,and we can design two types of attributes encryption strategy to make sure that different users could get their own decryption keys corresponding to their permissions.We encrypt the private data hierarchically with our algorithm to realize“precise”,“more accurate”,“fuzzy”and“private”four management modes,then users with higher permissions can access the private data inferior to their permissions.And we outsource some complex operations of decryption to DSP to ensure high efficiency on the premise of privacy protection.Finally,we analyze the efficiency and the security of our scheme.展开更多
In this paper, a nonlinear robust adaptive controller is proposed for gear transmission servo system (GTS) containing a sandwiched deadzone due to improper gear meshing. The controller is robust to dynamic uncertainti...In this paper, a nonlinear robust adaptive controller is proposed for gear transmission servo system (GTS) containing a sandwiched deadzone due to improper gear meshing. The controller is robust to dynamic uncertainties and can compensate the effect caused by the sandwiched nonlinearity which is separated from the control input through drive compliance. The proposed design methodology does not require an adaptive inverse deadzone function and does not require the knowledge of its parameter and only the knowledge of upper bounds is required.展开更多
以国家“86 3”计划重大项目和第八届国际铁氧体会议重要论文为据 ,综合分析、论述了低温烧结铁氧体粉料的进展状况。重点介绍了固相反应法 Ni Cu Zn铁氧体、Mg Cu Zn铁氧体和六角晶系 Co2 Z铁氧体。同时报道了具有世界领先水平的软化学...以国家“86 3”计划重大项目和第八届国际铁氧体会议重要论文为据 ,综合分析、论述了低温烧结铁氧体粉料的进展状况。重点介绍了固相反应法 Ni Cu Zn铁氧体、Mg Cu Zn铁氧体和六角晶系 Co2 Z铁氧体。同时报道了具有世界领先水平的软化学法 Ni Cu Zn铁氧体和六角晶系 Co2展开更多
A new watermarking algorithm resisting to geometric transformation based on singular value decomposition （SVD） in logarithm polar coordinate is proposed. The log-polar mapping （LPM） is used to resist rotation and ...A new watermarking algorithm resisting to geometric transformation based on singular value decomposition （SVD） in logarithm polar coordinate is proposed. The log-polar mapping （LPM） is used to resist rotation and scaling attacks, and the odd-even quantization algorithm is used to embed watermark so it can be extracted without the original host image. The experiments show that the proposed algorithm not only resists various geomet- ric attacks but also is robust enough to the common signal processing.展开更多
With the development of quantum computer, multivariate public key cryptography withstanding quantum attack has became one of the research focus. The existed signcryption schemes from discrete logarithm and bilinear pa...With the development of quantum computer, multivariate public key cryptography withstanding quantum attack has became one of the research focus. The existed signcryption schemes from discrete logarithm and bilinear paring are facing the serious threats. Based on multivariate public key cryptography, a new certificateless multi-receiver hybrid signcryption scheme has been proposed. The proposal reduced the cipher text and could handle arbitrary length messages by employing randomness reusing and hybrid encryption, as well as keeping security. In the random oracle model, the scheme＇s confidentiality could withstand the IND-CCA2 adversary and its unforgeability could withstand the UF-CMA adversary under the hardness of multivariat quadratic （MQ） problem and isomorphism of polynomials （IP） assumption. It has less computation overhead and higher transmission efficiency than others. It reduced 33% cipher data compared with the existed similar scheme.展开更多
In order to improve the accuracy and reduce the training and testing time in image classification algorithm, a novel image classification scheme based on extreme learning machine(ELM) and linear spatial pyramid matchi...In order to improve the accuracy and reduce the training and testing time in image classification algorithm, a novel image classification scheme based on extreme learning machine(ELM) and linear spatial pyramid matching using sparse coding(Sc SPM) for image classification is proposed. A new structure based on two layer extreme learning machine instead of the original linear SVM classifier is constructed. Firstly, the Sc SPM algorithm is performed to extract features of the multi-scale image blocks, and then each layer feature vector is connected to an ELM. Finally, the mapping features are connected together, and as the input of one ELM based on radial basis kernel function. With experimental evaluations on the well-known dataset benchmarks, the results demonstrate that the proposed algorithm has better performance not only in reducing the training time, but also in improving the accuracy of classification.展开更多
文摘The forthcoming European Higher Education Area has implied an important change in the teaching/learning process:it is necessary to get students more involved as well as to promote their independence and active participation.Furthermore,Information and Communication Technology is progressively including greater spaces in human beings’life,as economics,arts,engineering and education,among others fields.Therefore,a web tool,based on a content management system,has been developed to teach the Power Electronics subject.Moreover,the use of these multimedia tools makes it possible to encourage students’independence.This developed educational software is necessary as an important resource in the students’teaching/learning process.Therefore,the importance of evaluation models increases in as much as the application of these instruments allows its effective evaluation.It offers a greater guarantee of its use in these environments from the students’point of view.An evaluation process,by means of several surveys for students and lecturers,is used in order to evaluate the quality of these multimedia interactive tools.The results demonstrate that the use of this web tool increases students’motivation significantly.
文摘Electric Vehicle (EV) adoption is rapidly increasing, necessitating efficient and precise methods for predicting EV charging requirements. The early and precise prediction of the battery discharging status is helpful to avoid the complete discharging of the battery. The complete discharge of the battery degrades its lifetime and requires a longer charging duration. In the present work, a novel approach leverages the Edge Impulse platform for live prediction of the battery status and early alert signal to avoid complete discharging. The proposed method predicts the actual remaining useful life of batteries. A powerful edge computing platform utilizes Tensor Flow-based machine learning models to predict EV charging needs accurately. The proposed method improves the overall lifetime of the battery by the efficient utilization and precise prediction of the battery status. The EON-Tuner and DSP processing blocks are used for efficient results. The performance of the proposed method is analyzed in terms of accuracy, mean square error and other performance parameters.
文摘In this paper, a logistical regression statistical analysis (LR) is presented for a set of variables used in experimental measurements in reversed field pinch (RFP) machines, commonly known as “slinky mode” (SM), observed to travel around the torus in Madison Symmetric Torus (MST). The LR analysis is used to utilize the modified Sine-Gordon dynamic equation model to predict with high confidence whether the slinky mode will lock or not lock when compared to the experimentally measured motion of the slinky mode. It is observed that under certain conditions, the slinky mode “locks” at or near the intersection of poloidal and/or toroidal gaps in MST. However, locked mode cease to travel around the torus;while unlocked mode keeps traveling without a change in the energy, making it hard to determine an exact set of conditions to predict locking/unlocking behaviour. The significant key model parameters determined by LR analysis are shown to improve the Sine-Gordon model’s ability to determine the locking/unlocking of magnetohydrodyamic (MHD) modes. The LR analysis of measured variables provides high confidence in anticipating locking versus unlocking of slinky mode proven by relational comparisons between simulations and the experimentally measured motion of the slinky mode in MST.
文摘In this paper, a combination of model based adaptive design along with adaptive linear output feedback controller is used to compensate for robotic manipulator with output deadzone nonlinearity. The deadzone dynamics are utilized to adaptively estimate the deadzone parameter and a switching function is designed to eliminate the error produced in the adaptive observer dynamics. The overall design of the closed loop system ensures stability in the BIBO criterion.
基金supported by the National Natural Science Foundation of China (No. 51175502)
文摘In the helicopter transmission systems, it is important to monitor and track the tooth damage evolution using lots of sensors and detection methods. This paper develops a novel approach for sensor selection based on physical model and sensitivity analysis. Firstly, a physical model of tooth damage and mesh stiffness is built. Secondly, some effective condition indicators （Cls） are presented, and the optimal Cls set is selected by comparing their test statistics according to Mann-Kendall test. Afterwards, the selected CIs are used to generate a health indicator （HI） through sen slop estimator. Then, the sensors are selected according to the monotonic relevance and sensitivity to the damage levels. Finally, the proposed method is verified by the simulation and experimental data. The results show that the approach can provide a guide for health monitor- ing of helicopter transmission systems, and it is effective to reduce the test cost and improve the system＇s reliability.
文摘The mass attenuation coefficients(l/q) for different parts(root, flower, stem, and leaf) of three medicinal aromatic plants(Teucrium chamaedrys L. subsp. sinuatum,Rheum ribes, and Chrysophthalmum montanum) were measured using an ^(241)Am photon source in a stable geometry and calculated using the Monte Carlo N-Particle Transport Code System-extended(MCNPX) code and the WinXCOM program. The experimental and theoretical MCNPX and WinXCOM values exhibited good agreement.The measured mass attenuation coefficient values were then used to compute the effective atomic number(Z_(eff))and electron density(N_E) of the samples. The results reveal that S1-S(stem of Teucrium chamaedrys L. subsp. sinuatum) has the highest values of l/q and Zeff.
文摘In this study, the gamma radiation shielding features of several environmentally friendly materials were investigated. For this purpose, several attenuation parameters, such as the mass attenuation coefficient (l=q), radiation protection efficiency (RPE), and effective atomic number (Zeff) were determined experimentally and compared with numerical data obtained using WinXCom software. In the measurements, the emitted gamma photons were counted by a gamma spectrometer equipped with an HPGe detector using 22Na, 54Mn, 57Co, 60Co, 133Ba, and 137Cs radioactive point sources in the energy region of 81–1333 keV. The obtained results indicate that the l=q and RPE values of the samples decrease with an increase in photon energy. The experimental values are in good agreement with those obtained using WinXCom software. The RPE and Zeff results show that among the studied materials, the NaY0.77Yb0.20Er0.03F4 sample has the best gamma radiation shielding effectiveness.
基金supported by the National Natural Science Foundation of China under Grant No.50577028the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.20050487044the China Postdoctoral Science Foundation under Grant No.20080440931
文摘The skin effect in the reversely switched dynistor （RSD） devices is investigated in this paper. Based on the plasma bipolar drift model of the RSD, the current density distributions on the chip are simulated with considering the skin effect. The results indicate that the current density on the border can be several hundred to a thousand A/cm2 higher than that in the center of the chip. The skin effect becomes more prominent as the voltage increases and the inductance decreases in the main circuit. The phenomenon that most of a certain group of chips break over on the border has proved the existence of the skin effect.
基金supported in part by open project foundation of State Key Laboratory of Cryptology National Natural Science Foundation of China (NSFC) under Grant No. 61272492, No. 61572521 and No. 61309008Natural Science Foundation for Young of Shaanxi Province under Grant No. 2013JQ8013
文摘Matrix multiplication plays a pivotal role in the symmetric cipher algorithms, but it is one of the most complex and time consuming units, its performance directly affects the efficiency of cipher algorithms. Combined with the characteristics of VLIW processor and matrix multiplication of symmetric cipher algorithms, this paper extracted the reconfigurable elements and analyzed the principle of matrix multiplication, then designed the reconfigurable architecture of matrix multiplication of VLIW processor further, at last we put forward single instructions for matrix multiplication between 4×1 and 4×4 matrix or two 4×4 matrix over GF(2~8), through the instructions extension, the instructions could support larger dimension operations. The experiment shows that the instructions we designed supports different dimensions matrix multiplication and improves the processing speed of multiplication greatly.
基金supported by the National Natural Science Foundation of China(Grant No.61173131)the Fundamental Research Funds for the Interdisciplinary ClassMajor Projects for the Central Universities of Ministry of Education of China(Grant No.CDJZR12098801)+3 种基金the Based and Advanced Research Projects ofChongqing of China(Grant No.cstc2013jcyjA40033)the Key Strategic Project of Chongqing of China(Grant No.CSTC2009AB2230)the Strategeic Projectof Chongqing of China(Grant No.2009AC2057)the Special Funding for Scientific Research Project of Chongqing Postdoctoral Researchers,China(Grant No.XM20120054)
文摘In order to analyze the capacity stability of the time-varying-propagation and delay-dependent of mobile ad-hoc networks （MANETs）, in this paper, a novel approach is proposed to explore the capacity asymptotic stability for the delay- dependent of MANETs based on non-cooperative game theory, where the delay-dependent conditions are explicitly taken into consideration. This approach is based on the Lyapunov-Krasovskii stability theory for functional differential equations and the linear matrix inequality （LMI） technique. A corresponding Lyapunov-Krasovskii functional is introduced for the stability analysis of this system with use of the descriptor and ＂neutral-type＂ model transformation without producing any additional dynamics. The delay-dependent stability criteria are derived for this system. Conditions are given in terms of linear matrix inequalities, and for the first time referred to neutral systems with the time-varying propagation and delay- dependent stability for capacity analysis of MANETs. The proposed criteria are less conservative since they are based on an equivalent model transformation. Furthermore, we also provide an effective and efficient iterative algorithm to solve the constrained stability control model. Simulation experiments have verified the effectiveness and efficiency of our algorithm.
文摘Free-space optical (FSO) communication requires a line-of-sight connection between a transmitter and a receiver in which the information signal is modulated by an optical carrier that propagates in free space. The FSO channel is greatly affected by weather conditions such as fog, rain, and snow. In the literature, several adaptive techniques, such as power control (PC), have been suggested to mitigate channel link degradations. In this paper, we investigate the effects of snow and rain attenuation on the bit error rate (BER) of the FSO system using two types of modulations, the on-off keying (OOK) modulation and the pulse-position modulation (16-PPM). The effect of PC on the performance of FSO communications is also examined in this study. We evaluated the system’s performance with two types of snow, wet snow and dry snow, as well as with different rain regions. Results show that PC improves the BER of the FSO system;a high rate of improvement is found for wet snow and rain. PC has almost no effect with dry snow because of the high attenuation and the limitations on transmitted power. The BER for 16-PPM is better than that for OOK modulation.
基金This work is supported by National Natural Science Foundation of China (61572521, 61272492), Natural Science Basic Research Plan in Shaanxi Province of China (2015JM6353) and Foundation Funding Research Project of Engineering University of Chinese Armed Police Force (WJY201523).
文摘In the driven of big data, social computing and information security is undergoing rapid development and beginning to cross. This paper describes a key-policy attribute-based signcryption scheme which has less computation costs than existing similar schemes by utilizing secure outsourcing of scientific computation in cloud computing and eliminates overhead for users, the ciphertext is short, compact, the correctness of transformation algorithm is verifiable. The decrease of ciphertext is 17 %. Additionally, new scheme remits the key escrow problem and is proven selective security in the standard model, it could be verified publicly, applied in mobile devices.
文摘To solve the problems of data sharing in social network,such as management of private data is too loose,access permissions are not clear,mode of data sharing is too single and soon on,we design a hierarchical access control scheme of private data based on attribute encryption.First,we construct a new algorithm based on attribute encryption,which divides encryption into two phases,and we can design two types of attributes encryption strategy to make sure that different users could get their own decryption keys corresponding to their permissions.We encrypt the private data hierarchically with our algorithm to realize“precise”,“more accurate”,“fuzzy”and“private”four management modes,then users with higher permissions can access the private data inferior to their permissions.And we outsource some complex operations of decryption to DSP to ensure high efficiency on the premise of privacy protection.Finally,we analyze the efficiency and the security of our scheme.
文摘In this paper, a nonlinear robust adaptive controller is proposed for gear transmission servo system (GTS) containing a sandwiched deadzone due to improper gear meshing. The controller is robust to dynamic uncertainties and can compensate the effect caused by the sandwiched nonlinearity which is separated from the control input through drive compliance. The proposed design methodology does not require an adaptive inverse deadzone function and does not require the knowledge of its parameter and only the knowledge of upper bounds is required.
基金Supported by the National Natural Science Foundation of China (60842006)
文摘A new watermarking algorithm resisting to geometric transformation based on singular value decomposition （SVD） in logarithm polar coordinate is proposed. The log-polar mapping （LPM） is used to resist rotation and scaling attacks, and the odd-even quantization algorithm is used to embed watermark so it can be extracted without the original host image. The experiments show that the proposed algorithm not only resists various geomet- ric attacks but also is robust enough to the common signal processing.
基金Supported by the National Natural Science Foundation of China(61103231,61103230,61272492,61202492)the Project Funded by China Postdoctoral Science Foundation and Natural Science Basic Research Plan in Shaanxi Province of China(2014JQ8358,2014JQ8307,2014JM8300)
文摘With the development of quantum computer, multivariate public key cryptography withstanding quantum attack has became one of the research focus. The existed signcryption schemes from discrete logarithm and bilinear paring are facing the serious threats. Based on multivariate public key cryptography, a new certificateless multi-receiver hybrid signcryption scheme has been proposed. The proposal reduced the cipher text and could handle arbitrary length messages by employing randomness reusing and hybrid encryption, as well as keeping security. In the random oracle model, the scheme＇s confidentiality could withstand the IND-CCA2 adversary and its unforgeability could withstand the UF-CMA adversary under the hardness of multivariat quadratic （MQ） problem and isomorphism of polynomials （IP） assumption. It has less computation overhead and higher transmission efficiency than others. It reduced 33% cipher data compared with the existed similar scheme.
基金supported by the National Natural Science Foundation of China under Grant No. 61503424the Research Project by The State Ethnic Affairs Commission under Grant No. 14ZYZ017+1 种基金the Jiangsu Future Networks Innovation Institute-Prospective Research Project on Future Networks under Grant No. BY2013095-2-14the first-class discipline construction transitional funds of Minzu University of China
文摘In order to improve the accuracy and reduce the training and testing time in image classification algorithm, a novel image classification scheme based on extreme learning machine(ELM) and linear spatial pyramid matching using sparse coding(Sc SPM) for image classification is proposed. A new structure based on two layer extreme learning machine instead of the original linear SVM classifier is constructed. Firstly, the Sc SPM algorithm is performed to extract features of the multi-scale image blocks, and then each layer feature vector is connected to an ELM. Finally, the mapping features are connected together, and as the input of one ELM based on radial basis kernel function. With experimental evaluations on the well-known dataset benchmarks, the results demonstrate that the proposed algorithm has better performance not only in reducing the training time, but also in improving the accuracy of classification.
