CK Model Research Articles

A decentralized lightweight authentication protocol under blockchain

AbstractWith the continuous development of blockchain technology, blockchain gradually becomes to play an important role in the fields of finance, medicine, and new energy. In the certification of the membership of the blockchain, a third‐party certificate authority (CA) is used for certification. Considering the centralized structure of CA, and it is difficult for users to evaluate the credibility of CA. A decentralized blockchain membership authentication scheme and a key agreement protocol based on the elliptic curve are proposed by us. The protocol effectively addresses the credibility and single point of failure problems of centralized CAs in the traditional model. Through analysis, our scheme can effectively perform user registration and membership authentication instead of CAs. The security and correctness of the protocol was also analyzed using the formal protocol analysis tool ProVerif and the Ck model. The key authentication protocol we proposed can resist a variety of attacks, and the computational time consumption and Communication costs are relatively low.

Application of the Multi-Spectral Correlated-K Distribution Model for Oxy-Fuel Combustion

Thermal radiation is dominant in oxy-fuel combustion technology. When considering the difference between conventional air combustion and burgeoning oxy-fuel combustion caused by diverse components of fuel gas, it is critical to improve the accuracy of numerical simulation for radiation by CFD. The line-by-line model is considered as the most accurate approach to simulate thermal radiation while it will cost vast calculation resources on the other hand. This approach is applied as a benchmark for the validation of other approximate models in most cases. The corrected-K distribution method (CK) has attracted considerable attentions in recent years. the NBCk model always has an excellent performance when the temperature gradients are small. However, when the temperature gradient gets higher, the correlation assumption breaks down and leads to non-negligible errors. To improve the accuracy of the CK model, we introduced a new method called the multi spectral corrected-K distribution model based on the functional data analysis (FDA) in this work. The objective of this MSCK method is to group together wavenumbers according to the spectral scaling functions defined as the ratio between spectra in different thermophysical states. Over these intervals, the correlation assumption can be considered as nearly exact. Results show that the MSCK model always achieves a better performance on calculation accuracy while sharing the same computational cost as the traditional CK model.

A novel multi-stage distributed authentication scheme for smart meter communication.

Smart meters have ensured effective end-user energy consumption data management and helping the power companies towards network operation efficiency. However, recent studies highlighted that cyber adversaries may launch attacks on smart meters that can cause data availability, integrity, and confidentiality issues both at the consumer side or at a network operator’s end. Therefore, research on smart meter data security has been attributed as one of the top priorities to ensure the safety and reliability of the critical energy system infrastructure. Authentication is one of the basic building blocks of any secure system. Numerous authentication schemes have been proposed for the smart grid, but most of these methods are applicable for two party communication. In this article, we propose a distributed, dynamic multistage authenticated key agreement scheme for smart meter communication. The proposed scheme provides secure authentication between smart meter, NAN gateway, and SCADA energy center in a distributed manner. Through rigorous cryptanalysis we have proved that the proposed scheme resist replay attack, insider attack, impersonation attack and man-in-the-middle attack. Also, it provides perfect forward secrecy, device anonymity and data confidentiality. The proposed scheme security is formally proved in the CK—model and, using BAN logic, it is proved that the scheme creates a secure session between the communication participants. The proposed scheme is simulated using the AVISPA tool and verified the safety against all active attacks. Further, efficiency analysis of the scheme has been made by considering its computation, communication, and functional costs. The computed results are compared with other related schemes. From these analysis results, it is proved that the proposed scheme is robust and secure when compared to other schemes.

A comprehensive study on the transition metal–catalysed pyrolysis kinetics, thermodynamics and mechanisms of bamboo powder

Effects of Co(II), Ni(II) and Fe(III) impregnations on the pyrolysis behaviours of bamboo were investigated by using thermogravimetry and fixed-bed pyrolyser. Results reveal that the impregnated metals have significant effect on biomass devolatilization. Nickel impregnation increases the organic phase yield and relative amounts of tar in liquid phase. Cobalt impregnation drops cellulose degradation temperature and increases aqueous phase and non-condensable gas yields. Similarly, iron-impregnated biomass produces the highest amounts of biochar. Impregnated metals act as catalysts during pyrolysis and change degradation mechanism by lowering apparent activation energies and by changing thermodynamic parameters. Mean activation energies determined by three different isoconversional methods for normal and Co(II)-, Ni(II)- and F(III)-impregnated biomass are around 240, 197, 183 and 180 kJ.mol−1 respectively and similar to the values calculated by combined kinetic model (CK model). However, Kissinger method–based activation energy of Co(II)-impregnated biomass (295.9 kJ.mol−1) is quite high compared to the values predicted by isoconversional methods (~197 kJ.mol−1) and the CK model (197.7 kJ.mol−1). The observed results can be related to the complex degradation behaviour of Co(II)-impregnated biomass and the limitations on the uses of the Kissinger method in such a complex process. The CK model–based single-step pyrolysis mechanisms of normal and Co(II)-, Ni(II)- and Fe(III)-impregnated biomass are f(α) = (1-α)1.118.α−1.828, f(α) = (1-α)1.286.α−1.033, f(α) = (1-α)0.8895.α−1.898.[−ln(1-α)0.360] and f(α) = (1-α)0.8898.α−1.670.[−ln(1-α)0.060] respectively. The single-step CK model poorly explains biomass devolatilization behaviour. However, the same model can explain metal-impregnated biomass pyrolysis quite satisfactorily. Additionally, thermo-kinetic results obtained from various methods adequately explain the results obtained from thermogravimetric and fixed-bed pyrolysis experiments.

Application of the Multi-Spectral Correlated-k Distribution Model to Multi-Dimensional Rectangular Enclosure Gas Radiation Calculations

The Multi-Spectral Correlated-k distribution model (MSCk) is an amelioration of the widely used Ck model. In the MSCk model, the breakdown of correlation assumption used in the original Ck model for non-uniform media is overcome by introducing the clustering of scaling functions. The principle of MSCk model is to group together wavenumbers with respect to the spectral scaling functions—defined as the ratio between spectral absorption coefficients in distinct states—so that the correlation assumption can be considered as exact over the corresponding intervals of wavenumbers. Until now, validations of the MSCk model in 0D and 1D test cases have already been performed in the previous work (Andre, F., Hou, L., Roger, M. and Vaillon, R., 2014. The multispectral gas radiation modeling: A new theoretical framework based on a multidimensional approach to k-distribution methods. Journal of Quantitative Spectroscopy and Radiative Transfer, 147, pp.178–195; Andre, F., Hou, L. and Solovjov, V.P., 2016. An Exact Formulation of k-Distribution Methods in Non-Uniform Gaseous Media and its Approximate Treatment Within the Multi-Spectral Framework. Journal of Physics: Conference Series, 676(1)). However, its application to multi-dimensional configurations (much closer to industrial applications) has not been conducted. Accordingly, in the present paper, we focus our attention on the application of the MSCk model to Multi-dimensional calculations.

Heterogeneous Cross-Domain Identity Authentication Scheme Based on Proxy Resignature in Cloud Environment

Based on proxy resignature, the signature transformation between trust domains of different cryptographic systems is realized with the help of the cloud authentication center, so as to achieve cross-domain access between users and cloud service providers in heterogeneous environment. Hierarchical ID tree realizes the uniqueness of identity in communication, and the security of heterogeneous cross-domain identity authentication is enhanced by the two-factor authentication of “password + key” and temporary identity replacing real identity. The security of the scheme is proved under the CK model, which can anonymously trace entity identity, resist replay attacks, replacement attacks, and man-in-the-middle attacks, and the simulation experiment is carried out. By searching it in related fields, no paper on heterogeneous cross-domain identity authentication based on proxy resignature has been published yet. The results of this paper show that the proposed scheme has better computing performance and higher security.

Remote Sensing of High Temperature H2O–CO2 Mixture with the Multi-Spectral Correlated-k Distribution Model

Radiative heat transfer of gas plays an important role in remote sensing applications. Several models have been proposed to estimate the radiative properties of gases. The Line-By-Line (LBL) approach is the most accurate one. However, The Line-By-Line (LBL) approach usually requires excessive computation cost which makes it not applicable for most industrial most applications. Nevertheless, it still plays the role of benchmark reference for the assessment of other models. In this work, we propose the application of the Multi-Spectral Correlated-k distribution model (MSCk) so as to make the simulation of hot jet signature at long distance. In the MSCk model, the breakdown of correlation assumption used in the original Ck model for non-uniform media is overcome by introducing the clustering of scaling functions. The principle of MSCk model is to group together wavenumbers with respect to the spectral scaling functions-defined as the ratio between spectral absorption coefficients in distinct states-so that the correlation assumption can be considered as relatively exact over the corresponding intervals of wavenumbers. Results show that the MSCk model demonstrates better performance compared with the traditional Ck model at nearly an equivalent calculation cost.

Smart Contract-Based Cross-Domain Authentication and Key Agreement System for Heterogeneous Wireless Networks

Nowadays, it is still a major challenge to design a secure cross-domain authentication protocol for heterogeneous wireless networks with different security parameters. As a new technology, blockchain has attracted people’s attention because of its tamper-proof and decentralized characteristics. In this paper, we propose a cross-domain authentication and key agreement system based on smart contract of blockchains. Public keys of the nodes are managed using the smart contracts, and the system parameters are confirmed by contract query. On this basis, a cross-domain authentication and key agreement protocol is designed. In this protocol, roaming users can select temporary authentication parameters according to the system parameters of the roaming domain to complete authentication and key agreement, and users are anonymous in the process. Security of the protocol is demonstrated under the CK model, and two formal analysis tools are used to further analyze the protocol. Since the protocol does not have complex cryptographic operations and certificate verification, it has lower computational and communication overhead.

Assessment of engineering gas radiative property models in high pressure turbulent jet diffusion flames

This article aims to determine the most relevant engineering global method for gas radiative property modeling to be applied in the simulations of combustion problems. Two versions of the full-spectrum correlated k (FSCK) model, the Rank-Correlated full-spectrum k-distribution/ Spectral-Line-Weighted-sum-of-gray-gases (RC-FSK/RC-SLW) and a new version of the Weighted-Sum-of-Grey-Gases (WSGG) model are compared with the Narrow-Band CK (NBCK) model in four turbulent axisymmetric jet diffusion flames fueled either by hydrogen or methane at atmospheric and higher pressures. These comparisons are performed in decoupled radiative heat transfer calculations with the thermal fields being prescribed. The databases and coefficients associated to these different models are determined from a unique Line-By-Line database in order to allow a relevant comparison. Model results suggest that the SLW/FSCK methods coupled to the so-called improved scheme proposed by Cai and Modest or the Rank-Correlated SLW/FSK model, along with k-g distributions generated from accurate high-resolution high-temperature databases are the most mature gas radiative property models to be implemented in CFD codes dealing with combustion problems involving gas-soot mixtures.

Pressure effects on radiative heat transfer in sooting turbulent diffusion flames

This article investigates the effects of increasing pressure up to 4 atm on radiative heat transfer in momentum-driven methane turbulent jet flames by using well-established chemical mechanism, combustion, soot production and radiation models. A transported PDF method is used to close properly the soot-production turbulence interaction and the emission Turbulence Radiation Interaction (TRI). A Narrow-Band CK (NBCK) model is used as the gas radiative property model. The absorption TRI is neglected based on the Optically-Thin Fluctuation Approximation (OTFA). In accordance with a previous study dealing with non-sooting hydrogen flames (Nmira et al., JQSRT 220 (2018) 172–179), the 3-atm and 4-atm flames are designed from the atmospheric flame by using a Froude modeling approach that allows to preserve the flame/flow structure as the pressure is increased and hence to isolate the pressure effects on soot production, radiative heat transfer, and TRI. The effects of increasing pressure on radiant fraction result from two competing mechanisms: i) an increase in soot emission that tends to increase the radiant fraction and ii) a reduction in flame transparency that tends to reduce it. For the present flames, the first mechanism dominates the second, resulting in an increased radiant fraction with increasing the pressure. The TRI effects on flame radiative loss are also governed by competing mechanisms. The enhancement mechanism is due to gas emission TRI and temperature self-correlation effects on soot emission whereas the reduction mechanism is caused by the negative correlation between soot volume fraction and temperature. The former dominates whereas the latter becomes increasingly important with increasing the pressure. This limits the increase in the global radiative loss due to TRI as the pressure is increased. In addition, numerical simulations show that the TRI effects can reduce the local radiative loss in regions of high soot concentration of the 4 atm flame.

A Provably Secure and Lightweight Identity-Based Two-Party Authenticated Key Agreement Protocol for Vehicular Ad Hoc Networks

As an important part of smart cities, vehicle ad hoc networks (VANETs) have attracted much attention from both industry and academia. In a VANET, generating a secure session key to facilitate subsequent data-in-transit transfer between two or more vehicles is crucial, which can be achieved by using an authenticated key agreement protocol. However, most of the existing identity-based two-party authenticated key agreement protocols have significant computational requirements or are known to be insecure. Thus, in this paper, a secure and efficient identity-based two-party authenticated key agreement protocol is presented by us. This protocol does not involve complex bilinear pairing computations and can generate a valid session key in two rounds. The security of the proposed protocol is proved in the eCK model which has better capability to describe a protocol’s security than the famous CK model, and it has been widely used in the security proof of ID-based key agreement protocols currently. Additionally, we also evaluate its performance for potential utility in a VANET.

Effects of temperature, dry density and water content on the thermal conductivity of Genhe silty clay

As an important parameter to consider the thermal stability of road engineering in cold regions, thermal conductivity is largely affected by temperature, water content, dry density, and etc.. When investigating thermal conductivity, setting the dry densities and water contents of soil samples according to compaction curve agrees better with actual engineering conditions because of its compaction characteristic for subgrade soil. Therefore, experiments on thermal conductivity of 9 groups of soil samples corresponding to different water contents at the compaction curve were carried out under −40 ℃~20 ℃. It was found that thermal conductivity decreases linearly with the decrease of temperature in positive temperature range and increases exponentially in negative temperature range, which is closely connected to the variations of thermal conductivity, contents and interactions of every phase with temperature. Multiple linear regression analysis showed that water content has a slightly higher effect on thermal conductivity at positive temperature than that of dry density; however, its effect is about twice of that of dry density at negative temperature. Then, an assessment method combining Root Mean Square Error (RMSE) and Root Mean Square Value (Xrms) was proposed to evaluate the predictive capabilities of two classical models (Johansen’s model and the CK model) effectively.

Analysis of radiative transfer in a turbulent sooting jet flame using a Monte Carlo method coupled to large eddy simulation

Due to the relevant contribution of radiative transfer in the global energy balance of many industrial combustion systems, a deep understanding and accurate modelling of gas and soot radiative transfer is necessary. This topic is addressed here numerically in a canonical turbulent sooting configuration, i.e. an ethylene-air jet diffusion flame. The study is based on a coupled Monte Carlo - Large Eddy Simulation. In order to introduce as much physical details as possible, a recently-developed sectional model is used for soot particles description and the radiative transfer equation is solved using a Monte-Carlo method. A cK model describes gas radiative properties and the Rayleigh’s theory is considered for soot particles properties. Numerical results are compared to experimental data on radiative intensity measured along the flame height to validate the proposed methodology. Then, the different radiative contributions i.e. emission-absorption, gas-soot, are analyzed to study the nature of the radiative heat transfer in the investigated flame. Finally, turbulence-radiation interactions are quantified for the total mean emitted, absorbed and radiative powers. Closure of these effects on the mean emitted power is proposed and discussed. Opposite effects of turbulence-radiation interactions are observed for the gaseous and the soot contributions: the increase in mean emitted power for the gaseous phase is due to temperature fluctuations whereas a decrease of the solid phase contribution appears from a negative temperature-soot volume fraction correlation.

A new method of text information hiding based on open channel

Text is one of most constantly and widely used information carriers. Comparing with several other carriers, a new method of text information hiding based on open channel has been put forward in the article. The public normal text has been used to transmit information directly without any changes in order to hide it. At the same time, this hidden information negotiates with the intended recipient to produce the session key. The text including the location of hidden information and including the associated hidden rules delivers information through the session key. Besides, this method avoids stenographic testing used by attackers unless they break the session key, which ensures the hidden information's safety. The instruction protocol of hidden information serves as basic tool in proposed method. In the paper, the idea of the implicit authentication in the MTI protocol families (key agreement protocol constructed by Matsumoto, Takashima and Imai) derives from an identity-based protocol without pairing. Moreover, this proposed protocol is provably-secured in CK model (Canettikrawczyk model) for text information hiding.

Line by line benchmark solutions for radiative heat transfer in 2D irregular enclosures with non-gray media

Thermal radiation heat transfer in two-dimensional complex (irregular) enclosures containing non-gray gases, namely CO2/H2O/N2 mixtures, is calculated. The meshless Natural Element Method (NEM) is used for spatial discretization and the Discrete Ordinates Method (DOM) is employed for angular discretization of the radiative transfer equation. The Line-by-Line (LBL) and the correlated-k model (CK) models are used to model the spectral radiative properties of the participating gases. To obtain the most accurate results, the updated HITEMP spectroscopic database i.e. HITEMP2010 is employed in LBL calculations and the updated parameters (based on the HITEMP2010) is used in the CK calculation. The objectives of this study are threefold: (1) to combine a meshless natural elements method with LBL and the CK spectral models for the solution of radiative transfer problems in irregular (complex) enclosures, (2) to evaluate the accuracy of the CK model by comparing its results against the LBL results, and (3) to provide benchmark solutions for radiative heat transfer in irregular enclosures with the HITEMP2010 as the most accurate spectral database at high temperatures. Calculations are carried out for isothermal/non-isothermal and homogeneous/inhomogeneous mixtures of CO2/H2O/N2 gases. The present LBL results can serve as benchmark results for validating other approximate models in gas radiation heat transfer calculations in 2D complex enclosures. Results show that the CK results are in good agreement with those of the LBL model.

Practical indicators for assessing the magnitudes of wall radiative flux and of coupling effects between radiation and other heat transfer modes on the temperature law-of-the wall in turbulent gaseous boundary layers

Practical indicators are derived to compare radiative and conductive fluxes and the coupling effects of conduction, convection and radiation in turbulent gaseous boundary layers. A first criterion controlling the weight of wall radiative flux compared to wall conductive flux is introduced to assess the necessity of performing radiation simulation under given flow conditions. A second criterion based on the variation of the non-dimensional temperature due to radiation (scaled in wall units) is also developed to predict whether a wall model accounting for radiation is required when coupling effects become significant. These criteria are built from turbulent channel gaseous flow field simulations for many typical conditions, based on a k-∊ model, a given turbulent Prandtl number expression and a spectral CK model for radiation. They have been validated from the comparison with corresponding fully-coupled results where turbulent fields are solved numerically with direct numerical simulations and where the radiative energy transfer is solved with a Monte Carlo approach.The obtained criterion results are then presented and thoroughly analyzed on a large set of conditions, which would not have been feasible with direct numerical simulations or large-eddy simulations. The influence of system size, Reynolds number, wall emissivity and pressure is synthesized in 2D contour plots of interest for engineers and researchers to assess the magnitude of radiation effects in wall bounded flows.

A new method to model the thermal conductivity of soil–rock media in cold regions: An example from permafrost regions tunnel

Thermal conductivity of soil–rock media is an important index for analyzing the temperature field of cold region engineering. As a kind of mixed media, the thermal conductivity is determined by many factors, e.g. porosity, dry density, saturation degree, temperature, water content and so on. In this study, the thermal conductivity model of soil-rock media is established by multiple linear regression method based on the basic parameters of soil–rock samples. The significant testing (correlation coefficient R2, F-test and probability-of-F-to-enter) shows that the regression effect is well. To validate the multiple linear regression model, a comparison of the calculated values from the model with the tested data not used in the construction of the model shows that this model can effectively calculate thermal conductivity of soil–rock media. Additionally, compared with the other three general models, i.e. BP neural model, physical model and CK model, the multiple linear regression model is more reasonable and effective. Finally, based on the apparent heat capacity theory, a general regression model for soil–rock media in cold regions is obtained. It is hoped that a parameter basis can be provided for the temperature field simulation of cold region engineering from the study.

Security Integration of WAPI Based WLAN and 3G

To achieve the security inte-gration of 3G and WAPI based WLAN, a USIM based certificate distribution protocol is proposed. Two security integration schemes, i.e, loosely coupled and tightly coupled, are presented, which unify user management of 3G security architecture and WAPI, and realize WAPI based network access for 3G subscribers and identity privacy protection. The entity authentication and anonymity of the certificate distribution protocol is analyzed in CK model, and the results show that the protocol is provably secure.

Updated band model parameters for H2O, CO2, CH4 and CO radiation at high temperature

Statistical narrow-band (SNB) model parameters for H2O, CO2, CH4 and CO, and correlated-k (CK) parameters for H2O and CO2 are generated from line by line calculations and recently improved spectroscopic databases in wide temperature and spectral ranges. Results from the new parameters are compared to direct line by line calculations and to results from earlier model parameters [A. Soufiani, J. Taine, High temperature gas radiative property parameters of statistical narrow-band model for H2O, CO2 and CO and correlated-k (ck) model for H2O and CO2, Int. J. Heat Mass Transfer 40 (1997) 987–991] in terms of band averaged spectral transmissivities, Planck mean absorption coefficients, and total emissivities. The comparisons show first a good agreement between updated SNB, CK and LBL results. Significant improvements on earlier parameters are observed for H2O and CO2, especially at very high temperatures and path lengths. Model parameters and computer programs illustrating their implementation are provided as Supplementary data.

Provably secure authenticated key exchange protocol under the CDH assumption

Constructing a secure key exchange protocol is one of the most challenging problems in information security. We propose a provably secure two-round two-party authenticated key exchange (2AKE) protocol based on the well-studied CDH assumption in eCK model to provide the strongest definition of security for key exchange protocol when using the matching session to define the partnership. The underlying hardness assumption (CDH assumption) of our protocol is weaker than these of four other provably secure 2AKE protocols in CK model or eCK model and the computational cost of our protocol is reasonable. We also present a three-round variant of our protocol to realize key conformation.