We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. B...We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.展开更多
In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes tech...In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes technical exchanges and learning globally.Second,resources required for large model R&D are difficult for a single institution to obtain.The evaluation of general large models also requires the participation of experts from various industries.Third,without open source collaboration,it is difficult to form a unified upper-layer software ecosystem.Therefore,open source has become an important cooperation mechanism to promote the development of AI and large models.There are two cases to illustrate how open source and international standards interact with each other.展开更多
Integrated Sensing and Communication(ISAC)is considered a key technology in 6G networks.An accurate sensing channel model is crucial for the design and sensing performance evaluation of ISAC systems.The widely used Ge...Integrated Sensing and Communication(ISAC)is considered a key technology in 6G networks.An accurate sensing channel model is crucial for the design and sensing performance evaluation of ISAC systems.The widely used Geometry-Based Stochastic Model(GBSM),typically applied in standardized channel modeling,mainly focuses on the statistical fading characteristics of the channel.However,it fails to capture the characteristics of targets in ISAC systems,such as their positions and velocities,as well as the impact of the targets on the background.To address this issue,this paper proposes an Extended-GBSM(E-GBSM)sensing channel model that incorporates newly discovered channel characteristics into a unified modeling framework.In this framework,the sensing channel is divided into target and background channels.For the target channel,the model introduces a concatenated modeling approach,while for the background channel,a parameter called the power control factor is introduced to assess impact of the target on the background channel,making the modeling framework applicable to both mono-static and bi-static sensing modes.To validate the proposed model’s effectiveness,measurements of target and background channels are conducted across a wide range of indoor and outdoor scenarios,covering various sensing targets such as metal plates,reconfigurable intelligent surfaces,human bodies,unmanned aerial vehicles,and vehicles.The experimental results provide important theoretical support and empirical data for the standardization of ISAC channel modeling.展开更多
With the continuous development of the nursing discipline,standardized nurse training has always been a crucial link in the development of nursing science and plays an irreplaceable role in talent cultivation.However,...With the continuous development of the nursing discipline,standardized nurse training has always been a crucial link in the development of nursing science and plays an irreplaceable role in talent cultivation.However,in the current standardized training for some nurses,there are problems such as the simplification of nursing skill evaluation models and insufficient post competence of nurses.Therefore,optimizing the training model for nursing talents has become an inevitable measure.The problem-based learning(PBL)method and the Direct Observation of Procedural Skills(DOPS)evaluation model provide new directions and guidance for the development of training.Against this background,this paper explores effective approaches for standardized nurse training,starting from basic concepts and gradually delving into specific practical paths,aiming to improve the quality of talent cultivation and provide valuable references for other researchers.展开更多
Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the l...Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.展开更多
The deposition characteristics of nasal formulations directly determine the efficacy of the drugs,whilst the complexity of human nasal airway structure encumbers quantitative evaluation of nasal spatial deposition.Mal...The deposition characteristics of nasal formulations directly determine the efficacy of the drugs,whilst the complexity of human nasal airway structure encumbers quantitative evaluation of nasal spatial deposition.Male and female standard nasal airway structure models were calculated from computed tomography data of 128 Chinese Han nationality using statistical shape model.The deposition evaluation devices were further designed,and an imaging method was then employed to obtain drug deposition information.Furthermore,drug spatial deposition atlases were proposed by UV unwrapping,a mathematical mapping procedure flattening three-dimensional(3D)information to two-dimension bidirectionally,to achieve quantification of drug deposition fractions in the regions of interest.Moreover,the feasibility and universality of this method were verified by correlating it with the chemical quantitative results and computational fluid dynamic simulation of drug deposition of mometasone furoate nasal spray and hydroxypropyl methylcellulose nasal powder,respectively.Finally,the unique drug spatial deposition atlases of these two formulations in the male and female evaluation devices were generated,respectively.In summary,the standard nasal airway structure models of the Chinese Han nationality and the drug spatial deposition atlases provide scientific tools for the formulation optimization and quality control of nasal formulations.展开更多
Biological data in fishery ecology have complex structures and are highly heterogeneous.Catch per unit effort(CPUE)estimated from fishery-dependent data are often used to characterize abundance indices(AI)of fish spec...Biological data in fishery ecology have complex structures and are highly heterogeneous.Catch per unit effort(CPUE)estimated from fishery-dependent data are often used to characterize abundance indices(AI)of fish species,which is critical in fish stock assessment.However,additional considerations need to be undertaken to ensure robust estimation because of the latently complicated structures in fishery-dependent data.Here,we elaborated the process of constructing multi-output artificial neural network models to standardize CPUE for heterogeneous fishing operations and applied it to the skipjack tuna(Katsuwonus pelamis)in the western and central Pacific Ocean(WCPO).Seasonal,spatial,and environmental factors were input variables,and the CPUE of four types of skipjack tuna fisheries were set as output variables.The optimal structure for multi-output neural network was evaluated by systematic comparison in 100 runs hold-out cross-validation.The results showed that the final multi-output neural network model with high accuracy can predict the spatial and temporal trends of skipjack tuna abundance.展开更多
[Objective] The aim was to study on RBF model about evaluation on carrying capacity of water resources based on standardized indices. [Method] The indices were transformed and the averages of standard values in differ...[Objective] The aim was to study on RBF model about evaluation on carrying capacity of water resources based on standardized indices. [Method] The indices were transformed and the averages of standard values in different levels were taken as the standardized values of components of central vectors for basic functions of RBF hidden nodes. Hence, the basic functions are suitable for most indices, simplifying expression and calculation of basic functions. [Result] RBF models concluded through Monkey-king Genetic Algorithm with weights optimization are used in evaluation on water carrying capacity in three districts in Changwu County in Shaanxi Province, which were in consistent with that through fuzzy evaluation. [Conclusion] RBF, simple and practical, is universal and popular.展开更多
In this paper, we propose a new attribute-based proxy re-encryption scheme, where a semi-trusted proxy, with some additional information, can transform a ciphertext under a set of attributes into a new ciphertext unde...In this paper, we propose a new attribute-based proxy re-encryption scheme, where a semi-trusted proxy, with some additional information, can transform a ciphertext under a set of attributes into a new ciphertext under another set of attributes on the same message, but not vice versa, furthermore, its security was proved in the standard model based on decisional bilinear Diffie-Hellman assumption. This scheme can be used to realize fine-grained selectively sharing of encrypted data, but the general proxy rencryption scheme severely can not do it, so the proposed schemecan be thought as an improvement of general traditional proxy re-encryption scheme.展开更多
To understand fundamental problems in hypersonic laminar-turbulent boundary layer transition for three-dimensional complex vehicles,a new standard model with typical lifting-body features has been proposed,named as hy...To understand fundamental problems in hypersonic laminar-turbulent boundary layer transition for three-dimensional complex vehicles,a new standard model with typical lifting-body features has been proposed,named as hypersonic transition research vehicle(HyTRV).The configuration of HyTRV is fully analytical,and details of the design process are discussed in this study.The transition characteristics for HyTRV are investigated using three combined methods,i.e.,theoretical analyses,numerical simulations,and wind tunnel experiments.Results show that the fully analytic parameterization design of HyTRV can satisfy the model simplification requirements from both numerical simulations and wind tunnel experiments.Meanwhile,the flow field of HyTRV reveals typical transition mechanisms in six relatively separated regions,including the streamwise vortex instability,crossflow instability,secondary instability,and attachment-line instability.Therefore,the proposed HyTRV model is valuable for fundamental researches in hypersonic boundary layer transition.展开更多
The only known construction of key-insulated signature(KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is,the scheme requires two signatures:a signature with...The only known construction of key-insulated signature(KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is,the scheme requires two signatures:a signature with a master key and a signature with the signer's secret key. This folklore construction method leads to an ineffcient scheme. Therefore it is desirable to devise an effcient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters' signature scheme. It is computationally effcient and the signatures are short. The scheme is provably secure based on the diffculty of computational Diffe-Hellman(CDH) problem in the standard model.展开更多
Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This stu...Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion （Yungui Ecoregion）, China. The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus （TP） （total effect =-0.43）, and chlorophyll a （Chl-a） is recommended as the second important indicator （total effect =-0.41）. The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria （based on the reference conditions and the current environmental quality standards for surface water）. It is found that these candidate criteria cannot satisfy the designated 100% use-attainment. To achieve the short-term target （85% attainment of the designated use）, TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 μg/L, respectively. When used as a long-term target （90% or greater attainment of the designated use）, the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 μg/L, respectively.展开更多
Hierarchical identity based cryptography is a generalization of identity based encryption that mirrors an organizational hierarchy. It allows a root public key generator to distribute the workload by delegating public...Hierarchical identity based cryptography is a generalization of identity based encryption that mirrors an organizational hierarchy. It allows a root public key generator to distribute the workload by delegating public key generation and identity authentication to lower-level public key generators. Most hierarchical identity based signature schemes are provably secure in the random oracle model or the weak models without random oracles such as gauntlet-ID model. Currently, there is no hierarchical identity based signature scheme that is fully secure in the standard model, with short public parameters and a tight reduction. In this paper, a hierarchical identity based signature scheme based on the q-SDH problem that is fully secure in the standard model is proposed. The signature size is independent of the level of the hierarchy. Moreover, our scheme has short public parameters, high efficiency and a tight reduction.展开更多
Digital signature,as an important cryptographic primitive,has been widely used in many application scenarios,such as e-commerce,authentication,cloud computing,and so on.Certificateless Public Key Cryptography(PKC)can ...Digital signature,as an important cryptographic primitive,has been widely used in many application scenarios,such as e-commerce,authentication,cloud computing,and so on.Certificateless Public Key Cryptography(PKC)can get rid of the certificate management problem in the traditional Public Key Infrastructure(PKI)and eliminate the key-escrow problem in the identity-based PKC.Lately,a new Certificateless Signature(CLS)scheme has been proposed by Kyung-Ah Shim(IEEE SYSTEMS JOURNAL,2018,13(2)),which claimed to achieve provable security in the standard model.Unfortunately,we present a concrete attack to demonstrate that the scheme cannot defend against the Type I adversary.In this type of attack,the adversary can replace the public key of the signer,and then he plays the role of the signer to forge a legal certificateless signature on any message.Furthermore,we give an improved CLS scheme to resist such an attack.In terms of the efficiency and the signature length,the improved CLS is preferable to the original scheme and some recently proposed CLS schemes in the case of precomputation.展开更多
Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symp...Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.展开更多
There are very few researches on the shape standard curve currently,and they merely remain on the level of description of the general concept and production experiences,lacking of the in-depth theoretical analysis,and...There are very few researches on the shape standard curve currently,and they merely remain on the level of description of the general concept and production experiences,lacking of the in-depth theoretical analysis,and the concrete principle,method and steps for determining the shape standard curve are not put forward,therefore,they are not applicable in industrial production.This is the weakest spot in the research on the basic shape theory.In this paper,the basic shape standard curve and the transverse distribution curve of the exit thickness are attained with stepwise optimization,which is based on the theoretical calculation method of the shape standard curve of strip mills proposed by authors.By calculating the shape discrimination model and the shape forecast model separately,the simultaneous iterative calculation by the previous method is avoided,and the speed and stability of calculation are improved.The compensation models of the transverse temperature difference of the strip,the shape detection roller deflection and the shape of the strip coil are established,respectively,meantime,the basic shape standard curves are compensated,and the relatively perfect theoretical establishment method of the shape standard curve is formed.The simulation and calculation are done on a 1 220 mm five-stand cold strip tandem mill.The simulation and calculation result shows that the principle,method and steps for determining the shape standard curve are correct and feasible,and the correctness of theoretical analysis and calculation is verified.This paper proposes an idea and a method for the establishment of the shape standard curve in the rolling processes of cold strip mills,which develop the theory and model of the shape standard curve and improve the quality and efficiency of the shape control in the rolling processes of cold strip mills.展开更多
A directed signature is a type of signature with restricted verification ability.Directed signatures allow only a designated verifier to check the validity of the signature issued to him,and at the time of trouble or ...A directed signature is a type of signature with restricted verification ability.Directed signatures allow only a designated verifier to check the validity of the signature issued to him,and at the time of trouble or if necessary,any third party can verify the signature with the help of the signer or the designated verifier.Directed signature schemes are widely used in situations where the receiver's privacy should be protected.Proxy signatures allow an entity to delegate its signing capability to another entity in such a way that the latter can sign message on behalf of the former when the former is not available.Proxy signature schemes have found numerous practical applications such as distributed systems and mobile agent applications.In this paper,we firstly define the notion of the directed proxy signature by combining the proxy signature and directed signature.Then,we formalize its security model and present a concrete scheme in the standard model.Finally,we use the techniques from provable security to show that the proposed scheme is unforgeable under the gap Diffie-Hellman assumption,and invisible under the decisional Diffie-Hellman assumption.展开更多
To give concurrent consideration both the efficiency and the security(intensity of intractable problem) in the standard model,a chosen ciphertext secure identity-based broadcast encryption is proposed.Against the chos...To give concurrent consideration both the efficiency and the security(intensity of intractable problem) in the standard model,a chosen ciphertext secure identity-based broadcast encryption is proposed.Against the chosen ciphertext security model,by using identity(ID) sequence and adding additional information in ciphertext,the self-adaptive chosen identity security(the full security) and the chosen ciphertext security are gained simultaneously.The reduction of scheme's security is the decisional bilinear Diffie-Hellman(BDH) intractable assumption,and the proof of security shows that the proposed scheme is indistinguishable against adaptive chosen ciphertext attacks in the standard model under the decisional BDH intractable assumption.So the security level is improved,and it is suitable for higher security environment.展开更多
The weakly forced vibration of an axially moving viscoelastic beam is inves- tigated. The viscoelastic material of the beam is constituted by the standard linear solid model with the material time derivative involved....The weakly forced vibration of an axially moving viscoelastic beam is inves- tigated. The viscoelastic material of the beam is constituted by the standard linear solid model with the material time derivative involved. The nonlinear equations governing the transverse vibration are derived from the dynamical, constitutive, and geometrical relations. The method of multiple scales is used to determine the steady-state response. The modulation equation is derived from the solvability condition of eliminating secular terms. Closed-form expressions of the amplitude and existence condition of nontrivial steady-state response are derived from the modulation equation. The stability of non- trivial steady-state response is examined via the Routh-Hurwitz criterion.展开更多
To facilitate stability analysis of discrete-time bidirectional associative memory (BAM) neural networks, they were converted into novel neural network models, termed standard neural network models (SNNMs), which inte...To facilitate stability analysis of discrete-time bidirectional associative memory (BAM) neural networks, they were converted into novel neural network models, termed standard neural network models (SNNMs), which interconnect linear dynamic systems and bounded static nonlinear operators. By combining a number of different Lyapunov functionals with S-procedure, some useful criteria of global asymptotic stability and global exponential stability of the equilibrium points of SNNMs were derived. These stability conditions were formulated as linear matrix inequalities (LMIs). So global stability of the discrete-time BAM neural networks could be analyzed by using the stability results of the SNNMs. Compared to the existing stability analysis methods, the proposed approach is easy to implement, less conservative, and is applicable to other recurrent neural networks.展开更多
文摘We review a 3d quantum gravity model, which incorporates massive spinning fields into the Euclidean path integral in a Chern-Simons formulation. Fundamental matter as defined in our previous preon model is recapped. Both quantum gravity and the particle model are shown to be derivable from the supersymmetric 3d Chern-Simons action. Forces-Matter unification is achieved.
文摘In the era of AI,especially large models,the importance of open source has become increasingly prominent.First,open source allows innovation to avoid starting from scratch.Through iterative innovation,it promotes technical exchanges and learning globally.Second,resources required for large model R&D are difficult for a single institution to obtain.The evaluation of general large models also requires the participation of experts from various industries.Third,without open source collaboration,it is difficult to form a unified upper-layer software ecosystem.Therefore,open source has become an important cooperation mechanism to promote the development of AI and large models.There are two cases to illustrate how open source and international standards interact with each other.
基金supported in part by the Young Scientists Fund of the National Natural Science Foundation of China(No.62201087)in part by the National Natural Science Foundation of China(No.62525101,62341128)+3 种基金in part by the National Key R&D Program of China(No.2023YFB2904803)in part by the Guangdong Major Project of Basic and Applied Basic Research(No.2023B0303000001)in part by the Beijing Natural Science Foundation(No.L243002)in part by the Beijing University of Posts and Telecommunications-China Mobile Research Institute Joint innovation Center.
文摘Integrated Sensing and Communication(ISAC)is considered a key technology in 6G networks.An accurate sensing channel model is crucial for the design and sensing performance evaluation of ISAC systems.The widely used Geometry-Based Stochastic Model(GBSM),typically applied in standardized channel modeling,mainly focuses on the statistical fading characteristics of the channel.However,it fails to capture the characteristics of targets in ISAC systems,such as their positions and velocities,as well as the impact of the targets on the background.To address this issue,this paper proposes an Extended-GBSM(E-GBSM)sensing channel model that incorporates newly discovered channel characteristics into a unified modeling framework.In this framework,the sensing channel is divided into target and background channels.For the target channel,the model introduces a concatenated modeling approach,while for the background channel,a parameter called the power control factor is introduced to assess impact of the target on the background channel,making the modeling framework applicable to both mono-static and bi-static sensing modes.To validate the proposed model’s effectiveness,measurements of target and background channels are conducted across a wide range of indoor and outdoor scenarios,covering various sensing targets such as metal plates,reconfigurable intelligent surfaces,human bodies,unmanned aerial vehicles,and vehicles.The experimental results provide important theoretical support and empirical data for the standardization of ISAC channel modeling.
文摘With the continuous development of the nursing discipline,standardized nurse training has always been a crucial link in the development of nursing science and plays an irreplaceable role in talent cultivation.However,in the current standardized training for some nurses,there are problems such as the simplification of nursing skill evaluation models and insufficient post competence of nurses.Therefore,optimizing the training model for nursing talents has become an inevitable measure.The problem-based learning(PBL)method and the Direct Observation of Procedural Skills(DOPS)evaluation model provide new directions and guidance for the development of training.Against this background,this paper explores effective approaches for standardized nurse training,starting from basic concepts and gradually delving into specific practical paths,aiming to improve the quality of talent cultivation and provide valuable references for other researchers.
文摘Scientists have been searching for possible new particles beyond the standard model(SM),the theory that has predicted the building bricks that have constituted the known matter world today,including the Higgs-“the last”SM particle.
基金funded by the National Natural Science Foundation of China(No.82273863).
文摘The deposition characteristics of nasal formulations directly determine the efficacy of the drugs,whilst the complexity of human nasal airway structure encumbers quantitative evaluation of nasal spatial deposition.Male and female standard nasal airway structure models were calculated from computed tomography data of 128 Chinese Han nationality using statistical shape model.The deposition evaluation devices were further designed,and an imaging method was then employed to obtain drug deposition information.Furthermore,drug spatial deposition atlases were proposed by UV unwrapping,a mathematical mapping procedure flattening three-dimensional(3D)information to two-dimension bidirectionally,to achieve quantification of drug deposition fractions in the regions of interest.Moreover,the feasibility and universality of this method were verified by correlating it with the chemical quantitative results and computational fluid dynamic simulation of drug deposition of mometasone furoate nasal spray and hydroxypropyl methylcellulose nasal powder,respectively.Finally,the unique drug spatial deposition atlases of these two formulations in the male and female evaluation devices were generated,respectively.In summary,the standard nasal airway structure models of the Chinese Han nationality and the drug spatial deposition atlases provide scientific tools for the formulation optimization and quality control of nasal formulations.
基金supported by the National Key R&D Program of China(No.2023YFD2401303).
文摘Biological data in fishery ecology have complex structures and are highly heterogeneous.Catch per unit effort(CPUE)estimated from fishery-dependent data are often used to characterize abundance indices(AI)of fish species,which is critical in fish stock assessment.However,additional considerations need to be undertaken to ensure robust estimation because of the latently complicated structures in fishery-dependent data.Here,we elaborated the process of constructing multi-output artificial neural network models to standardize CPUE for heterogeneous fishing operations and applied it to the skipjack tuna(Katsuwonus pelamis)in the western and central Pacific Ocean(WCPO).Seasonal,spatial,and environmental factors were input variables,and the CPUE of four types of skipjack tuna fisheries were set as output variables.The optimal structure for multi-output neural network was evaluated by systematic comparison in 100 runs hold-out cross-validation.The results showed that the final multi-output neural network model with high accuracy can predict the spatial and temporal trends of skipjack tuna abundance.
基金Supported by National Natural Science Foundation of China (51179110)~~
文摘[Objective] The aim was to study on RBF model about evaluation on carrying capacity of water resources based on standardized indices. [Method] The indices were transformed and the averages of standard values in different levels were taken as the standardized values of components of central vectors for basic functions of RBF hidden nodes. Hence, the basic functions are suitable for most indices, simplifying expression and calculation of basic functions. [Result] RBF models concluded through Monkey-king Genetic Algorithm with weights optimization are used in evaluation on water carrying capacity in three districts in Changwu County in Shaanxi Province, which were in consistent with that through fuzzy evaluation. [Conclusion] RBF, simple and practical, is universal and popular.
基金the Natural Science Foundation of Shandong Province (Y2007G37)the Science and Technology Development Program of Shandong Province (2007GG10001012)
文摘In this paper, we propose a new attribute-based proxy re-encryption scheme, where a semi-trusted proxy, with some additional information, can transform a ciphertext under a set of attributes into a new ciphertext under another set of attributes on the same message, but not vice versa, furthermore, its security was proved in the standard model based on decisional bilinear Diffie-Hellman assumption. This scheme can be used to realize fine-grained selectively sharing of encrypted data, but the general proxy rencryption scheme severely can not do it, so the proposed schemecan be thought as an improvement of general traditional proxy re-encryption scheme.
基金This work was supported by the National Natural Science Foundation of China(Grant 11702315,92052301)the National Key Research and Development Program of China(Grant 2016YFA0401200).
文摘To understand fundamental problems in hypersonic laminar-turbulent boundary layer transition for three-dimensional complex vehicles,a new standard model with typical lifting-body features has been proposed,named as hypersonic transition research vehicle(HyTRV).The configuration of HyTRV is fully analytical,and details of the design process are discussed in this study.The transition characteristics for HyTRV are investigated using three combined methods,i.e.,theoretical analyses,numerical simulations,and wind tunnel experiments.Results show that the fully analytic parameterization design of HyTRV can satisfy the model simplification requirements from both numerical simulations and wind tunnel experiments.Meanwhile,the flow field of HyTRV reveals typical transition mechanisms in six relatively separated regions,including the streamwise vortex instability,crossflow instability,secondary instability,and attachment-line instability.Therefore,the proposed HyTRV model is valuable for fundamental researches in hypersonic boundary layer transition.
基金the National Natural Science Foundation of China (Nos. 60773092,60873229,60903178 and 60672072)the Zhejiang Provincial Natural Science Foundation of China (No. Y106505)+1 种基金the Fundamental Research Funds for the Central Universities (No. 2010B09614)the Foundation of Hohai University (No. 2084/409265)
文摘The only known construction of key-insulated signature(KIS) that can be proven secure in the standard model is based on the approach of using double signing. That is,the scheme requires two signatures:a signature with a master key and a signature with the signer's secret key. This folklore construction method leads to an ineffcient scheme. Therefore it is desirable to devise an effcient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters' signature scheme. It is computationally effcient and the signatures are short. The scheme is provably secure based on the diffculty of computational Diffe-Hellman(CDH) problem in the standard model.
基金supported by the Mega-projects of Science Research for Water Environment Improvement (No. 2009ZX07106-001-005-01)the National Nature Science Foundation of China (No. 71103166)
文摘Lake eutrophication （LE） has become an increasingly severe environmental problem recently. However, there has been no nutrient standard established for LE control in many developing countries such as China. This study proposes a structural equation model to assist in the establishment of a lake nutrient standard for drinking water sources in Yunnan-Guizhou Plateau Ecoregion （Yungui Ecoregion）, China. The modeling results indicate that the most predictive indicator for designated use-attainment is total phosphorus （TP） （total effect =-0.43）, and chlorophyll a （Chl-a） is recommended as the second important indicator （total effect =-0.41）. The model is further used for estimating the probability of use-attainment associated with lake water as a drinking water source and various levels of candidate criteria （based on the reference conditions and the current environmental quality standards for surface water）. It is found that these candidate criteria cannot satisfy the designated 100% use-attainment. To achieve the short-term target （85% attainment of the designated use）, TP and Chl-a values ought to be less than 0.02 mg/L and 1.4 μg/L, respectively. When used as a long-term target （90% or greater attainment of the designated use）, the TP and Chl-a values are suggested to be less than 0.018 mg/L and 1 μg/L, respectively.
基金Supported by the National Natural Science Foundation of China (6057303)the Program for New Century Excellent Talents in University by Ministry of Education (NCET-05-0398)
文摘Hierarchical identity based cryptography is a generalization of identity based encryption that mirrors an organizational hierarchy. It allows a root public key generator to distribute the workload by delegating public key generation and identity authentication to lower-level public key generators. Most hierarchical identity based signature schemes are provably secure in the random oracle model or the weak models without random oracles such as gauntlet-ID model. Currently, there is no hierarchical identity based signature scheme that is fully secure in the standard model, with short public parameters and a tight reduction. In this paper, a hierarchical identity based signature scheme based on the q-SDH problem that is fully secure in the standard model is proposed. The signature size is independent of the level of the hierarchy. Moreover, our scheme has short public parameters, high efficiency and a tight reduction.
基金partially supported by the National Natural Science Foundation of China under grant Nos.61872060 and 61772292the National Key R&D Program of China under grant No.2017YFB0802000+3 种基金Key Laboratory of Financial Mathematics of Fujian Province University(Putian University)under grant Nos.JR201806 and JR201901by the Natural Science Foundation of Fujian Province under grant Nos.2019J01752 and 2020J01905by the Program for Innovative Research Team in Science and Technology in Fujian Province University under grant No.2018-049by the Educational Research Projects of Young and Middle-aged Teachers in Fujian Education Department(JAT200514).
文摘Digital signature,as an important cryptographic primitive,has been widely used in many application scenarios,such as e-commerce,authentication,cloud computing,and so on.Certificateless Public Key Cryptography(PKC)can get rid of the certificate management problem in the traditional Public Key Infrastructure(PKI)and eliminate the key-escrow problem in the identity-based PKC.Lately,a new Certificateless Signature(CLS)scheme has been proposed by Kyung-Ah Shim(IEEE SYSTEMS JOURNAL,2018,13(2)),which claimed to achieve provable security in the standard model.Unfortunately,we present a concrete attack to demonstrate that the scheme cannot defend against the Type I adversary.In this type of attack,the adversary can replace the public key of the signer,and then he plays the role of the signer to forge a legal certificateless signature on any message.Furthermore,we give an improved CLS scheme to resist such an attack.In terms of the efficiency and the signature length,the improved CLS is preferable to the original scheme and some recently proposed CLS schemes in the case of precomputation.
基金National Key Research and Development Program of China,Grant/Award Number:2021YFF0702402National Natural Science Foundation of China,Grant/Award Number:32070531。
文摘Background:The Mongolian gerbil is an excellent laboratory animal for preparing the cerebral ischemia model due to its inherent deficiency in the circle of Willis.However,the low incidence and unpredictability of symptoms are caused by numerous complex variant types of the circle.Additionally,the lack of an evaluation system for the cer-ebral ischemia/reperfusion(I/R)model of gerbils has shackled the application of this model.Methods:We created a symptom-oriented principle and detailed neurobehavioral scoring criteria.At different time points of reperfusion,we analyzed the alteration in locomotion by rotarod test and grip force score,infarct volume by triphenyltetrazo-lium chloride(TTC)staining,neuron loss using Nissl staining,and histological charac-teristics using hematoxylin-eosin(H&E)straining.Results:With a successful model rate of 56%,32 of the 57 gerbils operated by our method harbored typical features of cerebral I/R injury,and the mortality rate in the male gerbils was significantly higher than that in the female gerbils.The suc-cessfully prepared I/R gerbils demonstrated a significant reduction in motility and grip strength at 1 day after reperfusion;formed obvious infarction;exhibited typi-cal pathological features,such as tissue edema,neuronal atrophy and death,and vacuolated structures;and were partially recovered with the extension of reperfu-sion time.Conclusion:This study developed a new method for the unilateral common carotid artery ligation I/R model of gerbil and established a standardized evaluation system for this model,which could provide a new cerebral I/R model of gerbils with more practical applications.
基金supported by National Hi-tech Research and Development Program of China(863Program,Grant No.2009AA04Z143)National Science and Technology Support Plan of China(Grant No.2007BAF02B10)Hebei Provincial Great Natural Science Foundation of China(Grant No.E2006001038)
文摘There are very few researches on the shape standard curve currently,and they merely remain on the level of description of the general concept and production experiences,lacking of the in-depth theoretical analysis,and the concrete principle,method and steps for determining the shape standard curve are not put forward,therefore,they are not applicable in industrial production.This is the weakest spot in the research on the basic shape theory.In this paper,the basic shape standard curve and the transverse distribution curve of the exit thickness are attained with stepwise optimization,which is based on the theoretical calculation method of the shape standard curve of strip mills proposed by authors.By calculating the shape discrimination model and the shape forecast model separately,the simultaneous iterative calculation by the previous method is avoided,and the speed and stability of calculation are improved.The compensation models of the transverse temperature difference of the strip,the shape detection roller deflection and the shape of the strip coil are established,respectively,meantime,the basic shape standard curves are compensated,and the relatively perfect theoretical establishment method of the shape standard curve is formed.The simulation and calculation are done on a 1 220 mm five-stand cold strip tandem mill.The simulation and calculation result shows that the principle,method and steps for determining the shape standard curve are correct and feasible,and the correctness of theoretical analysis and calculation is verified.This paper proposes an idea and a method for the establishment of the shape standard curve in the rolling processes of cold strip mills,which develop the theory and model of the shape standard curve and improve the quality and efficiency of the shape control in the rolling processes of cold strip mills.
基金the Natural Science Foundation of Shaanxi Province (No.2010JQ8017)the China Postdoctoral Science Foundation (No.2011M501427)the Special Found for Basic Scientific Research of Central Colleges of Chang’an University(No.CHD2012JC047)
文摘A directed signature is a type of signature with restricted verification ability.Directed signatures allow only a designated verifier to check the validity of the signature issued to him,and at the time of trouble or if necessary,any third party can verify the signature with the help of the signer or the designated verifier.Directed signature schemes are widely used in situations where the receiver's privacy should be protected.Proxy signatures allow an entity to delegate its signing capability to another entity in such a way that the latter can sign message on behalf of the former when the former is not available.Proxy signature schemes have found numerous practical applications such as distributed systems and mobile agent applications.In this paper,we firstly define the notion of the directed proxy signature by combining the proxy signature and directed signature.Then,we formalize its security model and present a concrete scheme in the standard model.Finally,we use the techniques from provable security to show that the proposed scheme is unforgeable under the gap Diffie-Hellman assumption,and invisible under the decisional Diffie-Hellman assumption.
基金the National Natural Science Foundation of China (No.60970119)the National Basic Research Program (973) of China (No.2007CB311201)
文摘To give concurrent consideration both the efficiency and the security(intensity of intractable problem) in the standard model,a chosen ciphertext secure identity-based broadcast encryption is proposed.Against the chosen ciphertext security model,by using identity(ID) sequence and adding additional information in ciphertext,the self-adaptive chosen identity security(the full security) and the chosen ciphertext security are gained simultaneously.The reduction of scheme's security is the decisional bilinear Diffie-Hellman(BDH) intractable assumption,and the proof of security shows that the proposed scheme is indistinguishable against adaptive chosen ciphertext attacks in the standard model under the decisional BDH intractable assumption.So the security level is improved,and it is suitable for higher security environment.
基金Project supported by the National Natural Science Foundation of China (No.10972143)the Shanghai Municipal Education Commission (No.YYY11040)+2 种基金the Shanghai Leading Academic Discipline Project (No.J51501)the Leading Academic Discipline Project of Shanghai Institute of Technology(No.1020Q121001)the Start Foundation for Introducing Talents of Shanghai Institute of Technology (No.YJ2011-26)
文摘The weakly forced vibration of an axially moving viscoelastic beam is inves- tigated. The viscoelastic material of the beam is constituted by the standard linear solid model with the material time derivative involved. The nonlinear equations governing the transverse vibration are derived from the dynamical, constitutive, and geometrical relations. The method of multiple scales is used to determine the steady-state response. The modulation equation is derived from the solvability condition of eliminating secular terms. Closed-form expressions of the amplitude and existence condition of nontrivial steady-state response are derived from the modulation equation. The stability of non- trivial steady-state response is examined via the Routh-Hurwitz criterion.
基金Project (No. 60074008) supported by the National Natural Science Foundation of China
文摘To facilitate stability analysis of discrete-time bidirectional associative memory (BAM) neural networks, they were converted into novel neural network models, termed standard neural network models (SNNMs), which interconnect linear dynamic systems and bounded static nonlinear operators. By combining a number of different Lyapunov functionals with S-procedure, some useful criteria of global asymptotic stability and global exponential stability of the equilibrium points of SNNMs were derived. These stability conditions were formulated as linear matrix inequalities (LMIs). So global stability of the discrete-time BAM neural networks could be analyzed by using the stability results of the SNNMs. Compared to the existing stability analysis methods, the proposed approach is easy to implement, less conservative, and is applicable to other recurrent neural networks.
