Emotion represents the feeling of an individual in a given situation. There are various ways to express the emotions of an individual. It can be categorized into verbal expressions, written expressions, facial express...Emotion represents the feeling of an individual in a given situation. There are various ways to express the emotions of an individual. It can be categorized into verbal expressions, written expressions, facial expressions and gestures. Among these various ways of expressing the emotion, the written method is a challenging task to extract the emotions, as the data is in the form of textual dat. Finding the different kinds of emotions is also a tedious task as it requires a lot of pre preparations of the textual data taken for the research. This research work is carried out to analyse and extract the emotions hidden in text data. The text data taken for the analysis is from the social media dataset. Using the raw text data directly from the social media will not serve the purpose. Therefore, the text data has to be pre-processed and then utilised for further processing. Pre-processing makes the text data more efficient and would infer valuable insights of the emotions hidden in it. The preprocessing steps also help to manage the text data for identifying the emotions conveyed in the text. This work proposes to deduct the emotions taken from the social media text data by applying the machine learning algorithm. Finally, the usefulness of the emotions is suggested for various stake holders, to find the attitude of individuals at that moment, the data is produced. .展开更多
In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust...In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust deduction factor has been developed, which combined the potential flow theory and boundary layer theory with the optimization technique. In the optimization process, the Sequential Unconstrained Minimization Technique(SUMT) interior point method of Nonlinear Programming(NLP) was proposed with the minimum thrust deduction factor as the objective function. An appropriate displacement is a basic constraint condition, and the boundary layer separation is an additional one. The parameters of the hull form modification function are used as design variables. At last, the numerical optimization example for lines of after-body of 50000 DWT product oil tanker was provided, which indicated that the propulsion efficiency was improved distinctly by this optimal design method.展开更多
In the test-field calibration,multi-azimuth stereo image pairs areproduced of the outdoor large control-field by the stereo-vision system under cali-bration.While in the analytical processing,the relationship between ...In the test-field calibration,multi-azimuth stereo image pairs areproduced of the outdoor large control-field by the stereo-vision system under cali-bration.While in the analytical processing,the relationship between image pairsis adopted as a constraint condition,which ensures the stability and quality of thecalibration results.This paper introduces the deduction process of the constraintconditions.展开更多
Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing ci...Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing circumstances, or achieved through numerous equipment operations. Therefore, a general deduction optimization scheme proposed is deemed to be necessary for the industry. In this paper, four parameters (cutting depth, feed rate, speed, tool nose runoff) with three levels (low, medium, high) are considered to optimize the tool wear for finish turning based on orthogonal array. Additionally, nine fuzzy control rules using triangle membership function with respective to five linguistic grades for tool wear are constructed. Considering four input and twenty output intervals, the defuzzification using center of gravity is then completed and introduced as the S/N (signal-to-noise) ratio. Thus, the optimum general deduction parameters can then be received. The confirmation experiment for optimum general deduction parameters is furthermore performed on an ECOCA-3807 CNC lathe. It is shown that the tool wear ratio from the fuzzy deduction optimization parameters is significantly advanced comparing to those from benchmark. This paper not only proposes a general deduction optimization scheme using orthogonal array, but also contributes the satisfactory fuzzy linguistic approach to tool wear in CNC turning with profound insight.展开更多
The function of Gastrointestinal tract including intestine is to a large degree mechanical.The mechanical properties of the intestinal wall,and the tonic (sustained) and/or phasic(short-
Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a nove...Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a novel approach for the design,analysis,management,control,and integration of CPSS,which can realize the causal analysis of complex systems by means of“algorithmization”of“counterfactuals”.However,because CPSS involve human and social factors(e.g.,autonomy,initiative,and sociality),it is difficult for traditional design of experiment(DOE)methods to achieve the generative explanation of system emergence.To address this challenge,this paper proposes an integrated approach to the design of computational experiments,incorporating three key modules:1)Descriptive module:Determining the influencing factors and response variables of the system by means of the modeling of an artificial society;2)Interpretative module:Selecting factorial experimental design solution to identify the relationship between influencing factors and macro phenomena;3)Predictive module:Building a meta-model that is equivalent to artificial society to explore its operating laws.Finally,a case study of crowd-sourcing platforms is presented to illustrate the application process and effectiveness of the proposed approach,which can reveal the social impact of algorithmic behavior on“rider race”.展开更多
For the problem of propositional satisfiability a polynomial algorithm of limited propositional deduction is proposed which can be viewed as a sort of boolean constraint propagation mechanism. It can be embodied in a ...For the problem of propositional satisfiability a polynomial algorithm of limited propositional deduction is proposed which can be viewed as a sort of boolean constraint propagation mechanism. It can be embodied in a backtracking search program for propositional satisfiability problems to make search efficient. The efficiency is gained in two ways:One is to use the algorithm to derive literals so as to overcome the ambiguities in search. The other is to exploit the consequence sets of unbound atoms generated during limited deduction as a heuristic measure for possible choices. The experiments have shown remarkable improvement in reducing search space.展开更多
In the last decade temporal logic has been developed into an effective means of specifying and proving properties of programs and behaviour of dynamic information systems.This note presents a natural deduction system ...In the last decade temporal logic has been developed into an effective means of specifying and proving properties of programs and behaviour of dynamic information systems.This note presents a natural deduction system (N system) of propositional temporal logic, which can be easily and immediately extended to other temporal logics.展开更多
A sequent is a pair(Г,△),which is true under an as-signment if either some formula inГis false,or some formula in △ is true.In L3-valued propositional logic,a mulisequent is a triple △|Θ|Г,which is true under a...A sequent is a pair(Г,△),which is true under an as-signment if either some formula inГis false,or some formula in △ is true.In L3-valued propositional logic,a mulisequent is a triple △|Θ|Г,which is true under an assignment if either some formula in △ has truth-value t,or some formula in Θ has truth-value m,or some formula in Г has truth-value£.Corre-spondingly there is a sound and complete Gentzen deduction system G for multisequents which is monotonic.Dually,a CO-multisequent is a triple △:Θ:Г,which is valid if there is an assignment v in which each formula in△has truth-value≠t,each formula in Θ has truth-value≠m,and each formula in Г has truth-value≠£.Correspondingly there is a sound and com-plete Gentzen deduction system G-for co-multisequents which is nonmonotonic.展开更多
Resolution modulo is an extension of first-order resolution in which rewrite rules are used to rewrite clauses during the search. In the first version of this method, clauses are rewritten to arbitrary propositions. T...Resolution modulo is an extension of first-order resolution in which rewrite rules are used to rewrite clauses during the search. In the first version of this method, clauses are rewritten to arbitrary propositions. These propositions are needed to be dynamically transformed into clauses. This unpleasant feature can be eliminated when the rewrite system is clausal, i.e., when it rewrites clauses to clauses. We show in this paper how to transform any rewrite system into a clausal one, preserving the existence of cut free proofs of any sequent.展开更多
The Fermat–Pramanik series are like below: .The mathematical principle has been established by factorization principle. The Fermat-Pramanik tree can be grown. It produces branched Fermat-Pramanik series using same pr...The Fermat–Pramanik series are like below: .The mathematical principle has been established by factorization principle. The Fermat-Pramanik tree can be grown. It produces branched Fermat-Pramanik series using same principle making Fermat-Pramanik chain. Branched chain can be propagated at any point of the main chain with indefinite length using factorization principle as follows: Same principle is applicable for integer solutions of A<sup>M</sup>+B<sup>2</sup>=C<sup>2</sup>which produces series of the type . It has been shown that this equation is solvable with N{A, B, C, M}. where , , M=M<sub>1</sub>+M<sub>2</sub> and M<sub>1</sub>>M<sub>2</sub>. Subsequently, it has been shown that using M= M<sub>1</sub>+M<sub>2</sub>+M<sub>3</sub>+... The combinations of Ms should be taken so that the values of both the parts (C<sub>n</sub>+B<sub>n</sub>) and (C<sub>n</sub>-B<sub>n</sub>) should be even or odd for obtaining Z{B,C}. Hence, it has been shown that the Fermat triple can generate a) Fermat-Pramanik multiplate, b) Fermat-Pramanik Branched multiplate and c) Fermat-Pramanik deductive series. All these formalisms are useful for development of new principle of cryptography. .展开更多
The philosophical foundation of the mainstream neoclassical economics is empirical philosophy.The controversies of economic methodology over inductive and deductive methods,over verificationistic and falsificationisti...The philosophical foundation of the mainstream neoclassical economics is empirical philosophy.The controversies of economic methodology over inductive and deductive methods,over verificationistic and falsificationistic approaches,and over positive and normative analyses in the evolution of economics are associated with those in the philosophy of science.The evolution of philosophy of science suggests that the above-mentioned pairs of economic methodologies should be appropriately combined when used in economics.It is not sensible to overemphasize either one inside each pair of economic methodologies.展开更多
In this paper, we consider the optimal risk sharing problem between two parties in the insurance business: the insurer and the insured. The risk is allocated between the insurer and the insured by setting a deductible...In this paper, we consider the optimal risk sharing problem between two parties in the insurance business: the insurer and the insured. The risk is allocated between the insurer and the insured by setting a deductible and coverage in the insurance contract. We obtain the optimal deductible and coverage by considering the expected product of the two parties' utilities of terminal wealth according to stochastic optimal control theory. An equilibrium policy is also derived for when there are both a deductible and coverage;this is done by modelling the problem as a stochastic game in a continuous-time framework. A numerical example is provided to illustrate the results of the paper.展开更多
This study had the purpose of testingtwo methods for teaching grammar in Englishasa Foreign Language(EFL)class:the deductive and inductive approaches in terms of effectiveness and rapport.This research was conducted i...This study had the purpose of testingtwo methods for teaching grammar in Englishasa Foreign Language(EFL)class:the deductive and inductive approaches in terms of effectiveness and rapport.This research was conducted in a public high school in Ecuador.Seventy students enrolled in the second year of senior high school participated.One in-service teacher taught the EFL classes during the process of intervention(10 weeks),and two EFL teachers observed all of these classes and recorded the information by filling in observation sheets.The students were administered grammar pretests and post-tests in order to assess their grammar knowledge.The results of the tests showed a significant difference in the scores in favor of the inductive approach.After the statistical analysis of the data obtained from the tests and observation sheets,we concluded that the inductive approach is more effective for teaching grammar in the EFL classroom in terms of instruction and rapport.展开更多
我在硕士研究生一年级的《电子商务概论》课程中采用“双语教学”已有4年时间了。该课程为每周3课时,共16周,计48学时,目前使用的教材是高等教育出版社出版的、教育部高等教育司推荐的“国外优秀信息科学与技术系列教材”中的影印版...我在硕士研究生一年级的《电子商务概论》课程中采用“双语教学”已有4年时间了。该课程为每周3课时,共16周,计48学时,目前使用的教材是高等教育出版社出版的、教育部高等教育司推荐的“国外优秀信息科学与技术系列教材”中的影印版教材“Electronic Commerce A Managerial Pcrspective(电子商务管理视角)”。讲课用比较详细的PowerPoint英语演示文稿。展开更多
The Counter-Propagation Deduction (CPD) method suggested by the authors is a new one for analyzing electromagnetic (EM) field in stratified media. The mechanism or the method is briefly introduced, and the rield in a ...The Counter-Propagation Deduction (CPD) method suggested by the authors is a new one for analyzing electromagnetic (EM) field in stratified media. The mechanism or the method is briefly introduced, and the rield in a layered medium in the presence or slant incidence of a perpendicularly or parallelly polarized electric wave is investigated. Some illustrative examples show that the method is capable of providing the direct mathematic expressions of the fields in an arbitrary layer, and is convenient for numerical evaluation through an unified program, irrespective of the number of medium layers.展开更多
An evaluation method of trial tests will be presented which is based on propeller characteristic functions provided by open water tests.Main reference quantity is the rate of revolutions which is constant during one t...An evaluation method of trial tests will be presented which is based on propeller characteristic functions provided by open water tests.Main reference quantity is the rate of revolutions which is constant during one trial double run and reliably to measure and,furthermore,the basic quantity of the mathematical adjustment of the hydrodynamically coupled test quantities by means of regression analysis.Using this physical plausible analysis of the trial test data and the propeller open water diagram an evaluation of current speed and ship’s speed through the water is possible.Assumed that thrust deduction fraction and relative rotative efficiency are scale independent,speed and power under contract conditions may be calculated at constant propeller speed where the results are corrected with respect to wind and waves using the linear dependance of speed and power at moderate differences of propeller load.展开更多
This paper focuses on the ducted propulsion with the accelerating nozzle,and discusses the influence of its fluid acceleration quality on its propulsive performances,including the hull efficiency,the relative rotative...This paper focuses on the ducted propulsion with the accelerating nozzle,and discusses the influence of its fluid acceleration quality on its propulsive performances,including the hull efficiency,the relative rotative efficiency,the effective wake,and the thrust deduction factor.An actual ducted propulsion system is used as an example for computational analysis.The computational conditions are divided into four combinations,which are provided with different propeller pitches,cambers,and duct lengths.Themethod applied in this study is the Computational Fluid Dynamics(CFD)technology,and the contents of the calculation include the hull’s viscous resistance,the wave-making resistance,the propeller performance curve,and the self-propulsion simulation in order to obtain the ship’s effective wake,thrust deduction factor,hull efficiency,and relative rotative efficiency.The performance curve of the propeller and resistance estimation results are compared with the experimental values for determining the correctness of the self-propulsion simulation.According to the computational analysis,it is known that increasing the propeller pitch cannot effectively increase the hull efficiency.The duct acceleration quality can be reduced by shortening the duct length;hence,when the effective wake fraction and thrust deduction factor decrease,the hull efficiency is increased.In addition,the pressure inside the duct is relatively low if the acceleration quality of the duct is too high,which is unfavorable for controlling the propeller cavitation.Moreover,if the hull bottom in front of the propeller is tapered up from the front to the back at an overly steep angle,the thrust deduction factor will be too large and lead to a relatively low hull efficiency.展开更多
Software Defined Network(SDN)deals with huge data processing units which possess network management.However,due to centralization behavior ensuring security in SDN is the major concern.In this work to ensure security,...Software Defined Network(SDN)deals with huge data processing units which possess network management.However,due to centralization behavior ensuring security in SDN is the major concern.In this work to ensure security,a security server has been at its aid to check the vulnerability of the networks and to keep an eye on the packet according to the screening policies.A Secure Shell Connection(SSH)is established by the security server which does a frequent inspection of the network’s logs.Malware detection and the Intrusion Detection System policies are also incorporated in the server for the effective scanning of the packets.In response to a suspicious log or the packets in the SDN network there is a change in the security norms.Hence the proposed work updates the security policies in accordance with the attacker mentality.展开更多
文摘Emotion represents the feeling of an individual in a given situation. There are various ways to express the emotions of an individual. It can be categorized into verbal expressions, written expressions, facial expressions and gestures. Among these various ways of expressing the emotion, the written method is a challenging task to extract the emotions, as the data is in the form of textual dat. Finding the different kinds of emotions is also a tedious task as it requires a lot of pre preparations of the textual data taken for the research. This research work is carried out to analyse and extract the emotions hidden in text data. The text data taken for the analysis is from the social media dataset. Using the raw text data directly from the social media will not serve the purpose. Therefore, the text data has to be pre-processed and then utilised for further processing. Pre-processing makes the text data more efficient and would infer valuable insights of the emotions hidden in it. The preprocessing steps also help to manage the text data for identifying the emotions conveyed in the text. This work proposes to deduct the emotions taken from the social media text data by applying the machine learning algorithm. Finally, the usefulness of the emotions is suggested for various stake holders, to find the attitude of individuals at that moment, the data is produced. .
基金financially supported by the National Natural Science Foundation of China(Grant No.51009087)
文摘In the preliminary design stage of the full form ships, in order to obtain a hull form with low resistance and maximum propulsion efficiency, an optimization design program for a full form ship with the minimum thrust deduction factor has been developed, which combined the potential flow theory and boundary layer theory with the optimization technique. In the optimization process, the Sequential Unconstrained Minimization Technique(SUMT) interior point method of Nonlinear Programming(NLP) was proposed with the minimum thrust deduction factor as the objective function. An appropriate displacement is a basic constraint condition, and the boundary layer separation is an additional one. The parameters of the hull form modification function are used as design variables. At last, the numerical optimization example for lines of after-body of 50000 DWT product oil tanker was provided, which indicated that the propulsion efficiency was improved distinctly by this optimal design method.
文摘In the test-field calibration,multi-azimuth stereo image pairs areproduced of the outdoor large control-field by the stereo-vision system under cali-bration.While in the analytical processing,the relationship between image pairsis adopted as a constraint condition,which ensures the stability and quality of thecalibration results.This paper introduces the deduction process of the constraintconditions.
文摘Tool wear is frequently considered in the modern CNC (computer numerical control) turning industry. Most existing optimization researches for CNC finish turning were either accomplished within certain manufacturing circumstances, or achieved through numerous equipment operations. Therefore, a general deduction optimization scheme proposed is deemed to be necessary for the industry. In this paper, four parameters (cutting depth, feed rate, speed, tool nose runoff) with three levels (low, medium, high) are considered to optimize the tool wear for finish turning based on orthogonal array. Additionally, nine fuzzy control rules using triangle membership function with respective to five linguistic grades for tool wear are constructed. Considering four input and twenty output intervals, the defuzzification using center of gravity is then completed and introduced as the S/N (signal-to-noise) ratio. Thus, the optimum general deduction parameters can then be received. The confirmation experiment for optimum general deduction parameters is furthermore performed on an ECOCA-3807 CNC lathe. It is shown that the tool wear ratio from the fuzzy deduction optimization parameters is significantly advanced comparing to those from benchmark. This paper not only proposes a general deduction optimization scheme using orthogonal array, but also contributes the satisfactory fuzzy linguistic approach to tool wear in CNC turning with profound insight.
文摘The function of Gastrointestinal tract including intestine is to a large degree mechanical.The mechanical properties of the intestinal wall,and the tonic (sustained) and/or phasic(short-
基金the National Key Research and Development Program of China(2021YFF0900800)the National Natural Science Foundation of China(61972276,62206116,62032016)+2 种基金the New Liberal Arts Reform and Practice Project of National Ministry of Education(2021170002)the Open Research Fund of the State Key Laboratory for Management and Control of Complex Systems(20210101)Tianjin University Talent Innovation Reward Program for Literature and Science Graduate Student(C1-2022-010)。
文摘Powered by advanced information technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).In this context,computational experiments method has emerged as a novel approach for the design,analysis,management,control,and integration of CPSS,which can realize the causal analysis of complex systems by means of“algorithmization”of“counterfactuals”.However,because CPSS involve human and social factors(e.g.,autonomy,initiative,and sociality),it is difficult for traditional design of experiment(DOE)methods to achieve the generative explanation of system emergence.To address this challenge,this paper proposes an integrated approach to the design of computational experiments,incorporating three key modules:1)Descriptive module:Determining the influencing factors and response variables of the system by means of the modeling of an artificial society;2)Interpretative module:Selecting factorial experimental design solution to identify the relationship between influencing factors and macro phenomena;3)Predictive module:Building a meta-model that is equivalent to artificial society to explore its operating laws.Finally,a case study of crowd-sourcing platforms is presented to illustrate the application process and effectiveness of the proposed approach,which can reveal the social impact of algorithmic behavior on“rider race”.
基金Project supported by the "863" High-Tech Program of China.
文摘For the problem of propositional satisfiability a polynomial algorithm of limited propositional deduction is proposed which can be viewed as a sort of boolean constraint propagation mechanism. It can be embodied in a backtracking search program for propositional satisfiability problems to make search efficient. The efficiency is gained in two ways:One is to use the algorithm to derive literals so as to overcome the ambiguities in search. The other is to exploit the consequence sets of unbound atoms generated during limited deduction as a heuristic measure for possible choices. The experiments have shown remarkable improvement in reducing search space.
基金Project supported by the National Natural Science Foundation of China, No. 6863022.
文摘In the last decade temporal logic has been developed into an effective means of specifying and proving properties of programs and behaviour of dynamic information systems.This note presents a natural deduction system (N system) of propositional temporal logic, which can be easily and immediately extended to other temporal logics.
文摘A sequent is a pair(Г,△),which is true under an as-signment if either some formula inГis false,or some formula in △ is true.In L3-valued propositional logic,a mulisequent is a triple △|Θ|Г,which is true under an assignment if either some formula in △ has truth-value t,or some formula in Θ has truth-value m,or some formula in Г has truth-value£.Corre-spondingly there is a sound and complete Gentzen deduction system G for multisequents which is monotonic.Dually,a CO-multisequent is a triple △:Θ:Г,which is valid if there is an assignment v in which each formula in△has truth-value≠t,each formula in Θ has truth-value≠m,and each formula in Г has truth-value≠£.Correspondingly there is a sound and com-plete Gentzen deduction system G-for co-multisequents which is nonmonotonic.
基金Supported by the French National Research Agency–National Natural Science Foundation of China under Grant No.61161130530National Natural Science Foundation of China under Grant No.60833001
文摘Resolution modulo is an extension of first-order resolution in which rewrite rules are used to rewrite clauses during the search. In the first version of this method, clauses are rewritten to arbitrary propositions. These propositions are needed to be dynamically transformed into clauses. This unpleasant feature can be eliminated when the rewrite system is clausal, i.e., when it rewrites clauses to clauses. We show in this paper how to transform any rewrite system into a clausal one, preserving the existence of cut free proofs of any sequent.
文摘The Fermat–Pramanik series are like below: .The mathematical principle has been established by factorization principle. The Fermat-Pramanik tree can be grown. It produces branched Fermat-Pramanik series using same principle making Fermat-Pramanik chain. Branched chain can be propagated at any point of the main chain with indefinite length using factorization principle as follows: Same principle is applicable for integer solutions of A<sup>M</sup>+B<sup>2</sup>=C<sup>2</sup>which produces series of the type . It has been shown that this equation is solvable with N{A, B, C, M}. where , , M=M<sub>1</sub>+M<sub>2</sub> and M<sub>1</sub>>M<sub>2</sub>. Subsequently, it has been shown that using M= M<sub>1</sub>+M<sub>2</sub>+M<sub>3</sub>+... The combinations of Ms should be taken so that the values of both the parts (C<sub>n</sub>+B<sub>n</sub>) and (C<sub>n</sub>-B<sub>n</sub>) should be even or odd for obtaining Z{B,C}. Hence, it has been shown that the Fermat triple can generate a) Fermat-Pramanik multiplate, b) Fermat-Pramanik Branched multiplate and c) Fermat-Pramanik deductive series. All these formalisms are useful for development of new principle of cryptography. .
基金the Research Project titled“The Role of the Global Development Initiative in Promoting Balanced,Coordinated and Inclusive Global Development”(ID:3162022ZYE03)and funded by the Basic Research Funds for Centrally Administered Institutions of Tertiary Education.
文摘The philosophical foundation of the mainstream neoclassical economics is empirical philosophy.The controversies of economic methodology over inductive and deductive methods,over verificationistic and falsificationistic approaches,and over positive and normative analyses in the evolution of economics are associated with those in the philosophy of science.The evolution of philosophy of science suggests that the above-mentioned pairs of economic methodologies should be appropriately combined when used in economics.It is not sensible to overemphasize either one inside each pair of economic methodologies.
基金supported by the NSF of China(11931018, 12271274)the Tianjin Natural Science Foundation (19JCYBJC30400)。
文摘In this paper, we consider the optimal risk sharing problem between two parties in the insurance business: the insurer and the insured. The risk is allocated between the insurer and the insured by setting a deductible and coverage in the insurance contract. We obtain the optimal deductible and coverage by considering the expected product of the two parties' utilities of terminal wealth according to stochastic optimal control theory. An equilibrium policy is also derived for when there are both a deductible and coverage;this is done by modelling the problem as a stochastic game in a continuous-time framework. A numerical example is provided to illustrate the results of the paper.
文摘This study had the purpose of testingtwo methods for teaching grammar in Englishasa Foreign Language(EFL)class:the deductive and inductive approaches in terms of effectiveness and rapport.This research was conducted in a public high school in Ecuador.Seventy students enrolled in the second year of senior high school participated.One in-service teacher taught the EFL classes during the process of intervention(10 weeks),and two EFL teachers observed all of these classes and recorded the information by filling in observation sheets.The students were administered grammar pretests and post-tests in order to assess their grammar knowledge.The results of the tests showed a significant difference in the scores in favor of the inductive approach.After the statistical analysis of the data obtained from the tests and observation sheets,we concluded that the inductive approach is more effective for teaching grammar in the EFL classroom in terms of instruction and rapport.
文摘我在硕士研究生一年级的《电子商务概论》课程中采用“双语教学”已有4年时间了。该课程为每周3课时,共16周,计48学时,目前使用的教材是高等教育出版社出版的、教育部高等教育司推荐的“国外优秀信息科学与技术系列教材”中的影印版教材“Electronic Commerce A Managerial Pcrspective(电子商务管理视角)”。讲课用比较详细的PowerPoint英语演示文稿。
文摘The Counter-Propagation Deduction (CPD) method suggested by the authors is a new one for analyzing electromagnetic (EM) field in stratified media. The mechanism or the method is briefly introduced, and the rield in a layered medium in the presence or slant incidence of a perpendicularly or parallelly polarized electric wave is investigated. Some illustrative examples show that the method is capable of providing the direct mathematic expressions of the fields in an arbitrary layer, and is convenient for numerical evaluation through an unified program, irrespective of the number of medium layers.
基金We are grateful for the support of the National Natural Science Foundation of China (U163215, 61472433, 61732022, 61732004, 61672020, and 61502517) and the National Key Research and Development Program (2016YFB0800802, 2016YFB0800803, 2016YFB0800804, 2017YFB0802204, 2016QY03D0601, 2016QY03D0603, and 2016YFB0800303).
文摘An evaluation method of trial tests will be presented which is based on propeller characteristic functions provided by open water tests.Main reference quantity is the rate of revolutions which is constant during one trial double run and reliably to measure and,furthermore,the basic quantity of the mathematical adjustment of the hydrodynamically coupled test quantities by means of regression analysis.Using this physical plausible analysis of the trial test data and the propeller open water diagram an evaluation of current speed and ship’s speed through the water is possible.Assumed that thrust deduction fraction and relative rotative efficiency are scale independent,speed and power under contract conditions may be calculated at constant propeller speed where the results are corrected with respect to wind and waves using the linear dependance of speed and power at moderate differences of propeller load.
文摘This paper focuses on the ducted propulsion with the accelerating nozzle,and discusses the influence of its fluid acceleration quality on its propulsive performances,including the hull efficiency,the relative rotative efficiency,the effective wake,and the thrust deduction factor.An actual ducted propulsion system is used as an example for computational analysis.The computational conditions are divided into four combinations,which are provided with different propeller pitches,cambers,and duct lengths.Themethod applied in this study is the Computational Fluid Dynamics(CFD)technology,and the contents of the calculation include the hull’s viscous resistance,the wave-making resistance,the propeller performance curve,and the self-propulsion simulation in order to obtain the ship’s effective wake,thrust deduction factor,hull efficiency,and relative rotative efficiency.The performance curve of the propeller and resistance estimation results are compared with the experimental values for determining the correctness of the self-propulsion simulation.According to the computational analysis,it is known that increasing the propeller pitch cannot effectively increase the hull efficiency.The duct acceleration quality can be reduced by shortening the duct length;hence,when the effective wake fraction and thrust deduction factor decrease,the hull efficiency is increased.In addition,the pressure inside the duct is relatively low if the acceleration quality of the duct is too high,which is unfavorable for controlling the propeller cavitation.Moreover,if the hull bottom in front of the propeller is tapered up from the front to the back at an overly steep angle,the thrust deduction factor will be too large and lead to a relatively low hull efficiency.
文摘Software Defined Network(SDN)deals with huge data processing units which possess network management.However,due to centralization behavior ensuring security in SDN is the major concern.In this work to ensure security,a security server has been at its aid to check the vulnerability of the networks and to keep an eye on the packet according to the screening policies.A Secure Shell Connection(SSH)is established by the security server which does a frequent inspection of the network’s logs.Malware detection and the Intrusion Detection System policies are also incorporated in the server for the effective scanning of the packets.In response to a suspicious log or the packets in the SDN network there is a change in the security norms.Hence the proposed work updates the security policies in accordance with the attacker mentality.