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A fossil-calibrated relaxed clock for Ephedra indicates an Oligocene age for the divergence of Asian and New World clades and Miocene dispersal into South America 被引量:7
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作者 Stefanie M.ICKERT-BOND Catarina RYDIN Susanne S.RENNER 《Journal of Systematics and Evolution》 SCIE CSCD 北大核心 2009年第5期444-456,共13页
Ephedra comprises approximately 50 species, which are roughly equally distributed between the Old and New World deserts, but not in the intervening regions (amphitropical range). Great heterogeneity in the substitut... Ephedra comprises approximately 50 species, which are roughly equally distributed between the Old and New World deserts, but not in the intervening regions (amphitropical range). Great heterogeneity in the substitution rates of Gnetales (Ephedra, Gnetum, and Welwitschia) has made it difficult to infer the ages of the major divergence events in Ephedra, such as the timing of the Beringian disjunction in the genus and the entry into South America. Here, we use data from as many Gnetales species and genes as available from GenBank and from a recent study to investigate the timing of the major divergence events. Because of the tradeoff between the amount of missing data and taxon/gene sampling, we reduced the initial matrix of 265 accessions and 12 loci to 95 accessions and 10 loci, and further to 42 species (and 7736 aligned nucleotides) to achieve stationary distributions in the Bayesian molecular clock runs. Results from a relaxed clock with an uncorrelated rates model and fossil-based calibration reveal that New World species are monophyletic and diverged from their mostly Asian sister clade some 30 mya, fitting with many other Beringian disjunctions. The split between the single North American and the single South American clade occurred approximately 25 mya, well before the closure of the Panamanian Isthmus. Overall, the biogeographic history of Ephedra appears dominated by long-distance dispersal, but finer-scale studies are needed to test this hypothesis. 展开更多
关键词 BIOGEOGRAPHY EPHEDRA relaxed molecular clock dating uncorrelated rates model.
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ASYNCHRONOUS RELAXED ITERATIVE METHODS FOR SOLVING LINEAR SYSTEMS OF EQUATIONS 被引量:3
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作者 谷同祥 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1997年第8期801-806,共6页
In this paper, the asynchronous versions of classical iterative methods for solving linear systems of equations are considered. Sufficient conditions for convergence of asynchronous relaxed processes are given for H-m... In this paper, the asynchronous versions of classical iterative methods for solving linear systems of equations are considered. Sufficient conditions for convergence of asynchronous relaxed processes are given for H-matrix by which nor only the requirements of [3] on coefficient matrix are lowered, but also a larger region of convergence than that in [3] is obtained. 展开更多
关键词 asynchronous iterative method relaxed method linear systems of equations
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INTRINSIC EQUATIONS FOR A GENERALIZED RELAXED ELASTIC LINE ON AN ORIENTED SURFACE IN THE GALILEAN SPACE 被引量:1
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作者 Tevfik SAHIN 《Acta Mathematica Scientia》 SCIE CSCD 2013年第3期701-711,共11页
In this article, we derive the intrinsic equations for a generalized relaxed elastic line on an oriented surface in the Galilean 3-dimensional space G3. These equations will give direct and more geometric approach to ... In this article, we derive the intrinsic equations for a generalized relaxed elastic line on an oriented surface in the Galilean 3-dimensional space G3. These equations will give direct and more geometric approach to questions concerning about generalized relaxed elastic lines on an oriented surface in G3. 展开更多
关键词 Galilean space generalized relaxed elastic line variational problem intrinsicformulation GEODESIC
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A Relaxed Greedy Block Kaczmarz Method for Solving Large Consistent Linear Systems 被引量:2
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作者 Yimou Liao Feng Yin Guangxin Huang 《Journal of Applied Mathematics and Physics》 2021年第12期3032-3044,共13页
Many problems in science and engineering require solving large consistent linear systems. This paper presents a relaxed greedy block Kaczmarz method (RGBK) and an accelerated greedy block Kaczmarz method (AGBK) for so... Many problems in science and engineering require solving large consistent linear systems. This paper presents a relaxed greedy block Kaczmarz method (RGBK) and an accelerated greedy block Kaczmarz method (AGBK) for solving large-size consistent linear systems. The RGBK algorithm extends the greedy block Kaczmarz algorithm (GBK) presented by Niu and Zheng in <a href="#ref1">[1]</a> by introducing a relaxation parameter to the iteration formulation of GBK, and the AGBK algorithm uses different iterative update rules to minimize the running time. The convergence of the RGBK is proved and a method to determine an optimal parameter is provided. Several examples are presented to show the effectiveness of the proposed methods for overdetermined and underdetermined consistent linear systems with dense and sparse coefficient matrix. 展开更多
关键词 Linear Consistent Systems Convergence Properties relaxed Greedy Block Kaczmarz
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Recent Research and Development Status of Relaxed Optics and Laser Technology: A Review 被引量:1
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作者 Petro Trokhimchuck 《Optics and Photonics Journal》 2021年第7期210-263,共54页
It is shown that for laser technologies it was necessary to create a new branch of physics: Relaxed Optics (synthesis of methods of the physical optics, quantum electronics, physical chemistry, physics of irreversible... It is shown that for laser technologies it was necessary to create a new branch of physics: Relaxed Optics (synthesis of methods of the physical optics, quantum electronics, physical chemistry, physics of irreversible phenomena in unitary system). It is allowed to explain complex chain processes of interaction light and matter. Possible applications of Relaxed Optical methods for the modeling of the laser-induced processes phenomena, including laser implantation (surface and subsurface processes), laser-induced optical breakdown (volume processes) and laser annealing of radiation and other defects in solid, are discussed. Perspectives of using these methods for the creation of new laser technologies, including creation new types of optoelectronic devices (heterostructures, diffraction lattices, etc.), resolution the problems of metallurgy, material science, painting, architecture and a building, are analyzed. 展开更多
关键词 Laser Technology relaxed Optics Laser-Induced Processes Laser Implantation HETEROSTRUCTURES Cascade Models Structural Coherence
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ALGEBRAIC MULTILEVEL RELAXED PRECONDITIONING METHODS
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作者 林鹭 《Numerical Mathematics A Journal of Chinese Universities(English Series)》 SCIE 1999年第2期221-230,共10页
Some ways of multilevel relaxed preconditioning matrices for the stiffness matrix in the discretization of selfad joint second order elliptic boundary value problems are proposed. For reason-able assumptions of the re... Some ways of multilevel relaxed preconditioning matrices for the stiffness matrix in the discretization of selfad joint second order elliptic boundary value problems are proposed. For reason-able assumptions of the relaxed factor ω, smaller relative condition numbers are given. The optimal relaxed factor ω is derived, too. 展开更多
关键词 relaxed PRECONDITIONING MULTILEVEL method RELATIVE CONDITIONING number.
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Three-step relaxed hybrid steepest-descent methods for variational inequalities
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作者 丁协平 林炎诚 姚任文 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2007年第8期1029-1036,共8页
The classical variational inequality problem with a Lipschitzian and strongly monotone operator on a nonempty closed convex subset in a real Hilbert space is studied. A new three-step relaxed hybrid steepest-descent m... The classical variational inequality problem with a Lipschitzian and strongly monotone operator on a nonempty closed convex subset in a real Hilbert space is studied. A new three-step relaxed hybrid steepest-descent method for this class of variational inequalities is introduced. Strong convergence of this method is established under suitable assumptions imposed on the algorithm parameters. 展开更多
关键词 variational inequalities relaxed hybrid steepest-descent method strong convergence nonexpansive mapping Hilbert space
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An Efficient and Practical Quantum Blind Signature Protocol with Relaxed Security Model
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作者 Jun Zhang Hao Xiao +1 位作者 Hongqun Zhai Xiaoli Meng 《Computers, Materials & Continua》 SCIE EI 2020年第4期301-313,共13页
Blind signature has a wide range of applications in the fields of E-commerce and block-chain because it can effectively prevent the blind signer from getting the original message with its blindness.Owing to the potent... Blind signature has a wide range of applications in the fields of E-commerce and block-chain because it can effectively prevent the blind signer from getting the original message with its blindness.Owing to the potential unconditional security,quantum blind signature(QBS)is more advantageous than the classical ones.In this paper,an efficient and practical quantum blind signature scheme relaxed security model is presented,where quantum superposition,decoy qubits and hash function are used for the purpose of blindness.Compared with previous QBS scheme,the presented scheme is more efficient and practical with a relaxed security model,in which the signer’s dishonest behavior can be detected other than being prevented as in other QBS schemes. 展开更多
关键词 Blind signature quantum superposition decoy qubit hash function relaxed security model
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Characteristics of an Indium-Rich InGaN p-n Junction Grown on a Strain-Relaxed InGaN Buffer Layer
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作者 杨莲红 张保花 郭福强 《Chinese Physics Letters》 SCIE CAS CSCD 2013年第4期174-176,共3页
An indium-rich InGaN p-n junction is grown on a strain-relaxed InGaN buffer layer.The results show that the n-InGaN is grown coherently on the buffer layer but the p-InGaN layer exhibits a partial strain relaxation.Th... An indium-rich InGaN p-n junction is grown on a strain-relaxed InGaN buffer layer.The results show that the n-InGaN is grown coherently on the buffer layer but the p-InGaN layer exhibits a partial strain relaxation.The fabricated InGaN p-n junction has a low reverse leakage current density on the order of 10^(-8)A/cm^(2)within the measured voltage range,and exhibits a wide spectral response due to the presence of band tail states or deep level states which origin from indium composition fluctuation or various defects.The measured peak responsivity at 438 nm is 31 mA/W at zero bias and reaches 118 mA/W at 3 V reverse bias.In addition,the Raman spectra of the p-and n-type InGaN alloys are also analyzed. 展开更多
关键词 INGAN relaxed INDIUM
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Strained Germanium-Tin pMOSFET Fabricated on a Silicon-on-Insulator Substrate with Relaxed Ge Buffer
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作者 苏少坚 韩根全 +4 位作者 张东亮 张广泽 薛春来 王启明 成步文 《Chinese Physics Letters》 SCIE CAS CSCD 2013年第11期195-198,共4页
Germanium-tin(Ge_(1-x)Sn_(x))p-type metal-oxide-semiconductor field effect transistors(pMOSFETs)were fabricated using a strained Ge_(0.985)Sn_(0.015) thin film that was epitaxially grown on a silicon-on-insulator subs... Germanium-tin(Ge_(1-x)Sn_(x))p-type metal-oxide-semiconductor field effect transistors(pMOSFETs)were fabricated using a strained Ge_(0.985)Sn_(0.015) thin film that was epitaxially grown on a silicon-on-insulator substrate with a relaxed Ge buffer layer.The Ge buffer was deposited using a two-step chemical vapor deposition growth technique.The high quality Ge_(0.985)Sn_(0.015) layer was grown by solid source molecular beam epitaxy.Ge_(0.985)Sn_(0.015) pMOSFETs with Si surface passivation,TaN/HfO_(2) gate stack,and nickel stanogermanide[Ni(Ge_(1-x)Sn_(x))]source/drain were fabricated on the grown substrate.The device achieves an effective hole mobility of 182 cm^(2)/V·s at an inversion carrier density of 1×10^(13) cm^(-2). 展开更多
关键词 technique DRAIN relaxed
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The Analysis of Impact Factors of Foreign Investment Based on Relaxed Lasso
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作者 Yanqi He 《Journal of Applied Mathematics and Physics》 2017年第3期693-699,共7页
Relaxed Lasso method is used for variable selection to 15 main economic factors affecting foreign investment. While Relaxed Lasso method, method of least squares and regression are compared, the result further reveals... Relaxed Lasso method is used for variable selection to 15 main economic factors affecting foreign investment. While Relaxed Lasso method, method of least squares and regression are compared, the result further reveals the main problem facing foreign investment at the present stage. 展开更多
关键词 relaxed Lasso VARIABLE SELECTION FOREIGN INVESTMENT
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On Solving a System of Volterra Integral Equations with Relaxed Monte Carlo Method
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作者 Zhimin Hong Xiangzhong Fang +1 位作者 Zaizai Yan Hui Hao 《Journal of Applied Mathematics and Physics》 2016年第7期1315-1320,共7页
A random simulation method was used for treatment of systems of Volterra integral equations of the second kind. Firstly, a linear algebra system was obtained by discretization using quadrature formula. Secondly, this ... A random simulation method was used for treatment of systems of Volterra integral equations of the second kind. Firstly, a linear algebra system was obtained by discretization using quadrature formula. Secondly, this algebra system was solved by using relaxed Monte Carlo method with importance sampling and numerical approximation solutions of the integral equations system were achieved. It is theoretically proved that the validity of relaxed Monte Carlo method is based on importance sampling to solve the integral equations system. Finally, some numerical examples from literatures are given to show the efficiency of the method. 展开更多
关键词 Systems of Volterra Integral Equations Quadrature Formula relaxed Monte Carlo Method Importance Sampling
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Relaxed Stable Stability Technology for an Air-to-air Missile
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作者 GUO Zheng-yu LIANG Xiao-geng 《International Journal of Plant Engineering and Management》 2012年第2期112-116,共5页
Relaxed Stable Stability (RSS) in an important part of the active control technology. It is a new way to raise the flying speed, distance and maneuverability of missile. Depth study of RSS technology plays an import... Relaxed Stable Stability (RSS) in an important part of the active control technology. It is a new way to raise the flying speed, distance and maneuverability of missile. Depth study of RSS technology plays an important role for the new concept missile design. This paper describes the detailed definition of RSS and its advantages, pres- ents the research status and prospects for its application in the design of new missiles. 展开更多
关键词 MISSILE active control technology relaxed stable stability new future missiles
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The Clockls Ticking Is Africa’s relaxed attitude toward timekeeping holding the continent back?
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作者 Mark Kapchanga 《ChinAfrica》 2013年第8期34-34,共1页
Africa misappropriates time as it does to other resources, such as minerals. With this tradition, everything on the continent is always running behind schedule.
关键词 The Clockls Ticking Is Africa’s relaxed attitude toward timekeeping holding the continent back
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Investigation on the Dimensional Properties of Relaxed Plain Knitted Fabrics 被引量:2
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作者 汪育桑 冯勋伟 《Journal of China Textile University(English Edition)》 EI CAS 2000年第2期19-22,共4页
A geometric model of relaxed plain-nitted fabric isproposed.A method based on the model for predictingthe loop length from the course spacing,wale spacing offabric and the diameter of yarn is deduced,as well as a comp... A geometric model of relaxed plain-nitted fabric isproposed.A method based on the model for predictingthe loop length from the course spacing,wale spacing offabric and the diameter of yarn is deduced,as well as a computer program is developed to graphically represent the structures of plain knitted fabric with various struc-tural parameters. 展开更多
关键词 DIMENSIONAL properties RELAXATION PLAIN KNITTED fabric loop length course and WALE SPACING
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Effect of Ion Dose on Growth of Relaxed SiGe Layer on Ion Implantation Si Substrate
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作者 Chen Changchun Liu Zhihong Huang Wentao Dou Weizhi Xiong Xiaoyi Zhang Wei Tsien Peihsin Cao Jianqing 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第z2期26-29,共4页
Thin strain-relaxed Si0.8Ge0.2 films (57.6 nm) on the 30 keV Ar+ ion implantation Si substrates for different dose (1 × 1014, 5 × 1014, 3 × 1015 cm-2) were grown by ultra high vacuum chemical vapor depo... Thin strain-relaxed Si0.8Ge0.2 films (57.6 nm) on the 30 keV Ar+ ion implantation Si substrates for different dose (1 × 1014, 5 × 1014, 3 × 1015 cm-2) were grown by ultra high vacuum chemical vapor deposition (UHVCVD) system.Rutherford backscattering/ion channeling (RBS/C), high resolution X-ray diffraction (HRXRD), Raman spectra as well as atomic force microscopy (AFM) were used to characterize these SiGe films. Investigations by RBS/C as well as HRXRD demonstrate that these thin Sio.8Geo.2 films could indeed epitaxially grow on the Ar+ ion implantation Si substrates. Under low dose ( 1 × 1014 cm-2) and medium dose (5 × 1014 cm-2) implantation conditions, the relaxation extents of SiGe films are 60.6% and 63.6%, respectively. However, high dose implantation (3 × 1015 cm-2) prompt the strain in epitaxial SiGe film to be close to full relaxation status (relaxation extent of 96.6% ). On the other hand, determinations of RBS/C also indicate the crystalline quality of SiGe film grown on high dose implantation Si substrate is nearly identical to that grown on low dose (1 × 1014 cm-2) implantation Si substrate. 展开更多
关键词 STRAIN RELAXATION UHVCVD ION IMPLANTATION SIGE
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RELAXED INERTIAL METHODS FOR SOLVING SPLIT VARIATIONAL INEQUALITY PROBLEMS WITHOUT PRODUCT SPACE FORMULATION
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作者 Grace Nnennaya OGWO Chinedu IZUCHUKWU Oluwatosin Temitope MEWOMO 《Acta Mathematica Scientia》 SCIE CSCD 2022年第5期1701-1733,共33页
Many methods have been proposed in the literature for solving the split variational inequality problem.Most of these methods either require that this problem is transformed into an equivalent variational inequality pr... Many methods have been proposed in the literature for solving the split variational inequality problem.Most of these methods either require that this problem is transformed into an equivalent variational inequality problem in a product space,or that the underlying operators are co-coercive.However,it has been discovered that such product space transformation may cause some potential difficulties during implementation and its approach may not fully exploit the attractive splitting nature of the split variational inequality problem.On the other hand,the co-coercive assumption of the underlying operators would preclude the potential applications of these methods.To avoid these setbacks,we propose two new relaxed inertial methods for solving the split variational inequality problem without any product space transformation,and for which the underlying operators are freed from the restrictive co-coercive assumption.The methods proposed,involve projections onto half-spaces only,and originate from an explicit discretization of a dynamical system,which combines both the inertial and relaxation techniques in order to achieve high convergence speed.Moreover,the sequence generated by these methods is shown to converge strongly to a minimum-norm solution of the problem in real Hilbert spaces.Furthermore,numerical implementations and comparisons are given to support our theoretical findings. 展开更多
关键词 split variational inequality problems relaxation technique inertial extrapolation minimum-norm solutions product space formulation half-spaces
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Approximations to Isentropic Planar Magneto-Hydrodynamics Equations by Relaxed Euler-Type Systems
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作者 Yachun LI Zhaoyang SHANG +1 位作者 Chenmu WANG Liang ZHAO 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2024年第3期413-440,共28页
In this paper,the authors consider an approximation to the isentropic planar Magneto-hydrodynamics(MHD for short)equations by a kind of relaxed Euler-type system.The approximation is based on the generalization of the... In this paper,the authors consider an approximation to the isentropic planar Magneto-hydrodynamics(MHD for short)equations by a kind of relaxed Euler-type system.The approximation is based on the generalization of the Maxwell law for non-Newtonian fuids together with the Maxwell correction for the Ampere law,hence the approximate system becomes a first-order quasilinear symmetrizable hyperbolic systems with partial dissipation.They establish the global-in-time smooth solutions to the approximate Euler-type equations in a small neighbourhood of constant equilibrium states and obtain the global-in-time convergence towards the isentropic planar MHD equations.In addition,they also establish the global-in-time error estimates of the limit based on stream function techniques and energy estimates for error variables. 展开更多
关键词 Planar MHD equations Relaxation limits Global convergence Stream function
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Distribution/correlation-free test for two-sample means in high-dimensional functional data with eigenvalue decay relaxed
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作者 Kaijie Xue 《Science China Mathematics》 SCIE CSCD 2023年第10期2337-2346,共10页
We propose a methodology for testing two-sample means in high-dimensional functional data that requires no decaying pattern on eigenvalues of the functional data.To the best of our knowledge,we are the first to consid... We propose a methodology for testing two-sample means in high-dimensional functional data that requires no decaying pattern on eigenvalues of the functional data.To the best of our knowledge,we are the first to consider and address such a problem.To be specific,we devise a confidence region for the mean curve difference between two samples,which directly establishes a rigorous inferential procedure based on the multiplier bootstrap.In addition,the proposed test permits the functional observations in each sample to have mutually different distributions and arbitrary correlation structures,which is regarded as the desired property of distribution/correlation-free,leading to a more challenging scenario for theoretical development.Other desired properties include the allowance for highly unequal sample sizes,exponentially growing data dimension in sample sizes and consistent power behavior under fairly general alternatives.The proposed test is shown uniformly convergent to the prescribed significance,and its finite sample performance is evaluated via the simulation study and an application to electroencephalography data. 展开更多
关键词 high dimension functional data eigenvalue decay relaxed multiplier bootstrap distribution/correlation-free
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An application-semantics-based relaxed transaction model for internetware 被引量:6
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作者 HUANG Tao DING Xiaoning WEI Jun 《Science in China(Series F)》 2006年第6期774-791,共18页
An internetware application is composed by existing individual services, while transaction processing is a key mechanism to make the composition reliable. The existing research of transactional composite service (TCS... An internetware application is composed by existing individual services, while transaction processing is a key mechanism to make the composition reliable. The existing research of transactional composite service (TCS) depends on the analysis to composition structure and exception handling mechanism in order to guarantee the relaxed atomicity. However, this approach cannot handle some application-specific requirements and causes lots of unnecessary failure recoveries or even aborts. In this paper, we propose a relaxed transaction model, including system mode, relaxed atomicity criterion, static checking algorithm and dynamic enforcement algorithm. Users are able to define different relaxed atomicity constraint for different TCS according to application-specific requirements, including acceptable configurations and the preference order. The checking algorithm determines whether the constraint can be guaranteed to be satisfied. The enforcement algorithm monitors the execution and performs transaction management work according to the constraint. Compared to the existing work, our approach can handle complex application requirements, avoid unnecessary failure recoveries and perform the transaction management work automatically. 展开更多
关键词 INTERNETWARE service composition relaxed atomicity relaxed transaction mode.
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