A Comparative Study of Genetic Algorithm Parameters for the Inverse Problem-based Fault Diagnosis of Liquid Rocket Propulsion Systems

Fault diagnosis of liquid rocket propulsion systems （LRPSs） is a very important issue in space launch activities particularly when manned space missions are accompanied, since the safety and reliability can be significantly enhanced by exploiting an efficient fault diagnosis system. Currently, inverse problem-based diagnosis has attracted a great deal of research attention in fault diagnosis domain. This methodology provides a new strategy to model-based fault diagnosis for monitoring the health of propulsion systems. To solve the inverse problems arising from the fault diagnosis of LRPSs, GAs have been adopted in recent years as the first and effective choice of available numerical optimization tools. However, the GA has many control parameters to be chosen in advance and there still lack sound theoretical tools to analyze the effects of these parameters on diagnostic performance analytically. In this paper a comparative study of the influence of GA parameters on diagnostic results is conducted by performing a series of numerical experiments. The objective of this study is to investigate the contribution of individual algorithm parameter to final diagnostic result and provide reasonable estimates for choosing GA parameters in the inverse problem-based fault diagnosis of LRPSs. Some constructive remarks are made in conclusion and will be helpful for the implementation of GA to the fault diagnosis practice of LRPSs in the future.

Doping Evolution of the Superconducting Gap Structure in Heavily Hole-Doped Ba1-xKxFe2As2:a Heat Transport Study

We perform systematic thermal conductivity measurements on heavily hole-doped Ba1-xKxFe2As2 single crystals with 0.747 ≤ x ≤ 0.974. At x=0.747, the K0/T is negligible, indicating a nodeless superconducting gap. A small residual linear term K0/T （=0.035 m W.K-2 cm-1） appears at xz0.826, and it increases slowly up to x=0.974, followed by a substantial increase of more than 20 times to of K0/T clearly shows that the nodal gap appears near x surface topology. The small values of K0/T from x=0.826 the pure KFe2As2 （x=1.0）. This doping dependence = 0.8, possibly associated with the change of Fermi to 0.974 are consistent with the Y-shaped nodal s- wave gap recently revealed by angle-resolved photoemission spectroscopy experiments at x=0.9. Furthermore, the substantial increase of K0/T from x=0.974 to 1.0 is inconsistent with a symmetry-imposed d-wave gap in KFe2 As2, and a possible nodal gap structure in KFe2As2 is discussed.

A Comparative Study on the Tense-Aspect of Auxiliary in English and Chinese

The aim of the paper is to give a general comparison about the structural composition of the AUX in English and Chinese mainly from the perspective of tense-aspect.Based on the basic construction of English AUX system,which includes such elements as Tense,Modal,Perfect aspect,Progressive aspect and Passive,the paper focuses on comparing the syntactic characteristics of tense element in the two languages.The final part of the paper briefly summarized predicted learning problems that Chinese learners of English as well as English learners of Chinese would have in learning English and Chinese respectively.

Doping Induced Gap Anisotropy in Iron-Based Superconductors:a Point-Contact Andreev Reflection Study of BaFe2-xNixAs2 Single Crystals

We report a systematic investigation on c-axis point-contact Andreev reflection （PCAR） in BaFe2-xNixAs2 superconducting single crystals from underdoped to overdoped regions （0.075≤ x ≤0.15）. At low temperatures, an in-gap sharp peak at low-bias voltage is observed in PCAR for overdoped samples, in contrast to the case of underdoped junctions, in which an in-gap plateau is observed. The variety of the conductance spectra with doping can be well described by using a generalized Blonder-Tinkham-Klapwijk formalism with an angle-dependent gap. This gap shows a clear crossover from a nodeless in the underdoped side to a nodal feature in the overdoped region. This result provides evidence of the doping-induced evolution of the superconducting order parameter when the inter-pocket and intra-pocket scattering are tuned through doping, as expected in the s± scenario.

A Critical Review of “A Comparative study of the effects of input-based and production-based instruction on vocabulary acquisition by young EFL learners”

A critical review of an article titled"A Comparative study of the effects of input-based and production-based instruction on vocabulary acquisition by young EFL learners"will be conducted. On the one hand, the reviewed study has reached its significance in the achievement of the comparative effects of input-based and production-based tasks on vocabulary acquisition. On the other hand, some problems can be found in the study, from research method to its discussion. The present paper is devoted to analyzing main aspects of the article one by one and providing corresponding suggestions.

Bending of Timoshenko beam with effect of crack gap based on equivalent spring model

Considering the effect of crack gap, the bending deformation of the Timoshenko beam with switching cracks is studied. To represent a crack with gap as a nonlinear unidirectional rotational spring, the equivalent flexural rigidity of the cracked beam is derived with the generalized Dirac delta function. A closed-form general solution is obtained for bending of a Timoshenko beam with an arbitrary number of switching cracks. Three examples of bending of the Timoshenko beam are presented. The influence of the beam＇s slenderness ratio, the crack＇s depth, and the external load on the crack state and bending performances of the cracked beam is analyzed. It is revealed that a cusp exists on the deflection curve, and a jump on the rotation angle curve occurs at a crack location. The relation between the beam＇s deflection and load is bilinear, each part corresponding to an open or closed state of crack, respectively. When the crack is open, flexibility of the cracked beam decreases with the increase of the beam＇s slenderness ratio and the decrease of the crack depth. The results are useful in identifying non-destructive cracks on a beam.

Towards sustainable intensification of apple production in China—Yield gaps and nutrient use effi ciency in apple farming systems

China is in a dominant position in apple production globally with both the largest apple growing area and the largest export of fresh apple fruits. However, the annual productivity of China＇s apple is significantly lower than that of other dominant apple producing countries. In addition, apple production is based on excessive application of chemical fertilizers and the nutrient use efficiency （especially nitrogen） is therefore low and the nutrient emissions to the environment are high. Apple production in China is considerably contributes to farmers＇ incomes and is important as export product. There is an urgent need to enhance apple productivity and improve nutrient use efficiencies in intensive apple production systems in the country. These can be attained by improved understanding of production potential, yield gaps, nutrient use and best management in apple orchards. To the end, priorities in research on apple production systems and required political support are described which may lead to more sustainable and environmental-friendly intensification of apple production in China.

Gap Functions and Error Bounds for Set-Valued Vector Quasi Variational Inequality Problems

One of the classical approaches in the analysis of a variational inequality problem is to transform it into an equivalent optimization problem via the notion of gap function. The gap functions are useful tools in deriving the error bounds which provide an estimated distance between a specific point and the exact solution of variational inequality problem. In this paper, we follow a similar approach for set-valued vector quasi variational inequality problems and define the gap functions based on scalarization scheme as well as the one with no scalar parameter. The error bounds results are obtained under fixed point symmetric and locally α-Holder assumptions on the set-valued map describing the domain of solution space of a set-valued vector quasi variational inequality problem.

A Density Functional Study of N-Doped TiO_2 Anatase Cluster

A systematic study on geometry, electronic structure and vibrational properties of N-doped TiO2 anatase cluster, within the framework of the density functional theory, has been performed in this work. The calculations confirmed that the most structures in substitutional model consist of a two-coordinate bridge structure and a three-coordinate hollow structure. The calculated results can well explain the red shift in N-doped TiO2 observed in experiments. The study provides an illustration for the N-doped anatase from the viewpoint of chemical bonding theory.

A Survey on Basic Business Problems of Pistachio Farmers in Turkey

Turkey is an important country which has pistachio trees in the world. The Southeastern Anatolia Project （GAP） region located in southeastern of Anatolia has all of pistachio trees. In other words, pistachio trees have grown only in GAP region. Provinces of ~anliurfa, Gaziantep and Adiyaman are in the GAP region. In this study, we have investigated problems of pistachio farmers in these cities. So, we applied survey to pistachio farmers. Then we analyzed data which we had from the surveys with SPSS. As a result, the farmers have mainly got input problems, marketing problems, processing problems, keeping problems, financial problems, labor problems and managerial problems. As a solution, pistachio farmers must set up cooperatives which help finding inputs, markets, loan, labor, manager them and come up with their problems. Government has to support pistachio farmers and price of pistachio yield, pistachio farmers must have training programs about theirs works. Finally, pistachio nuts of stock market must be surely founded.

A Case Study on Primary Problem Student in Yemen

Nowadays,problem student is a common phenomenon exiting in primary and secondary school,Yemen.However,current unknown is why problem students appear and how to make an effective intervention way for reducing the problem behaviors.Although there have been many researches about problem student's problem behaviors researches on causes,developmental mechanism and educational strategies of problem students mainly stay on the theoretical research stage.This study aimed to investigate main reason for the formation of problem students and then make an effective intervention way and examine the invention effect.Firstly,combining existing research literature and teaching experience,this study sums up that problem behavior of problem students is mainly learning problem,interpersonal problem and willpower problem.Secondly,this study selected ten"problem students"of primary school as the participants.They are simply classified into three categories in accordance with the severity of the problem behaviors of problem students.I summarized various causes and affecting factors of problem behaviors through observing their performances and behaviors,and conduct in-depth interviews and explorations throughout the whole research process.Thirdly,on the basis of kind and severity of problems,various flexibly methods were used for the intervention study of problem behaviors.After that,I conducted interviews with the study cases,parents and teachers once again and made tracked records for the intervention effect.The intervention achieves marked improvement.For example,most students greatly improve their behaviors in class.Finally,I reflect the research process itself,considering that the case study is necessary method for the issue of"problem students".The use of qualitative research method is more conducive to enter the inner world of the studying cases,and better understand their true conditions as well.And on this basis,it is easier to find a breakthrough in the problem to improve the"problem students"and make a closer link between theoretical research and practical application.

Complex variable solution for boundary value problem with X-shaped cavity in plane elasticity and its application*

A new type of displacement pile, the X-section cast-in-place concrete （XCC） pile, has recently been developed in China. Extensive field tests and laboratory experi- ments are undertaken to evaluate its performance and quantify the non-uniform deforma- tion effect （NUDE） of the X-shaped cross section during installation. This paper develops a simplified theoretical model that attempts to capture the NUDE. Based on the theory of complex variable plane elasticity, closed-form solutions of the stress and displacement for the X-shaped cavity boundary value problem are given. Subsequently, the analytical solution is used to evaluate the NUDE, the concrete filling index （CFI）, and the perimeter reduction coefficient of the XCC pile cross section. The computed results are compared with field test results, showing reasonable agreement. The present simplified theoretical model reveals the deformation mechanism of the X-shaped cavity and facilitates applica- tion of the newly developed XCC pile technique in geotechnical engineering.

Clinical features of multiple gastrointestinal stromal tumors:A pooling analysis combined with evidence and gap map

BACKGROUND Multiple gastrointestinal stromal tumors(MGISTs)are a very rare type of gastrointestinal stromal tumor(GIST)and are usually observed in syndrome.AIM The paper aimed to describe the clinical and oncological features of MGISTs and to offer evidence for the diagnosis and treatment.METHODS Data of consecutive patients with MGISTs who were diagnosed at Peking University People’s Hospital(PKUPH)from 2008 to 2019 were retrospectively evaluated.Further,a literature search was conducted by retrieving data from PubMed,EMBASE,and the Cochrane library databases from inception up to November 30,2019.RESULTS In all,12 patients were diagnosed with MGISTs at PKUPH,and 43 published records were ultimately included following the literature review.Combined analysis of the whole individual patient data showed that female(59.30%),young(14.45%),and syndromic GIST(63.95%)patients comprised a large proportion of the total patient population.Tumors were mainly located in the small intestine(58.92%),and both CD117 and CD34 were generally positive.After a mean 78.32-mo follow-up,the estimated median overall survival duration(11.5 years)was similar to single GISTs,but recurrence-free survival was relatively poorer.CONCLUSION The clinical and oncological features are potentially different between MGISTs and single GIST.Further studies are needed to explore appropriate surgical approach and adjuvant therapy.

Landscape Economics: Connotations, Basic Problems and Research Methods

This paper analyzed necessity and laws of natural and cultural resource consumption and creation activities as a branch of economics or research direction, proposed such basic frameworks of landscape economics such as connotations, basic problems and research methods on the basis of sorting out literature. Landscape economics is a social science focusing on the public preferences for natural and humanistic landscapes, and the preference evolution laws, economic laws of landscape resource consumption and creation activities. The basic problems include evaluation of landscape resource value, optimal utilization of landscape resources, landscape resource development and protection policies, formation and creation of diversified landscape structure. The research methods include investigation of consumers' willingness, experiment and behavioral economics, logical reasoning, and case study.

Determination of Causal Effect in Observational Studies： Analysis of Correlated Data with Binary End-Points

Identifying the causal impact of＇ some intervention challenging when one is faced with correlated binary end-points in observational studies is a challenging task, and it is even more The statistical literature on analyzing such data is well documented. Dependence between observations from the same study subject in correlated data renders invalid the usual chi-square tests of independence and inflates the variance ofparameter estimates. Disaggregated approaches such as hierarchical linear models which are able to adjust for individual level covariate：s are favoured in the analysis of such data, thereby gaining power over aggregated and individual-level analyses. In this article the authors, therefore, address the issue of analyzing correlated data with dichotomous end-points by using hierarchical logistic regression, a generalization of the standard logistic regression model for independent outcomes.

On Teaching Consonants for Freshmen of English Majors

When study English phonetics,Chinese learners will meet many difficulties,which need teachers to deal with.This paper is to discuss about how to teach consonants.

New smooth gap function for box constrained variational inequalities

A new smooth gap function for the box constrained variational inequality problem （VIP） is proposed based on an integral global optimality condition. The smooth gap function is simple and has some good differentiable properties. The box constrained VIP can be reformulated as a differentiable optimization problem by the proposed smooth gap function. The conditions, under which any stationary point of the optimization problem is the solution to the box constrained VIP, are discussed. A simple frictional contact problem is analyzed to show the applications of the smooth gap function. Finally, the numerical experiments confirm the good theoretical properties of the method.

A Bi-Objective Green Vehicle Routing Problem: A New Hybrid Optimization Algorithm Applied to a Newspaper Distribution

The purpose of this work is to present a methodology to provide a solution to a Bi-objective Green Vehicle Routing Problem (BGVRP). The methodology, illustrated using a case study (newspaper distribution problem) and literature Instances, was divided into three stages: Stage 1, data treatment;Stage 2, “metaheuristic approaches” (hybrid or non-hybrid), used comparatively, more specifically: NSGA-II (Non-dominated Sorting Genetic Algorithm II), MOPSO (Multi-Objective Particle Swarm Optimization), which were compared with the new approaches proposed by the authors, CWNSGA-II (Clarke and Wright’s Savings with the Non-dominated Sorting Genetic Algorithm II) and CWTSNSGA-II (Clarke and Wright’s Savings, Tabu Search and Non-dominated Sorting Genetic Algorithm II);Stage 3, analysis of the results, with a comparison of the algorithms. An optimization of 19.9% was achieved for Objective Function 1 (OF1;minimization of CO2 emissions) and consequently the same percentage for the minimization of total distance, and 87.5% for Objective Function 2 (OF2;minimization of the difference in demand). Metaheuristic approaches hybrid achieved superior results for case study and instances. In this way, the procedure presented here can bring benefits to society as it considers environmental issues and also balancing work between the routes, ensuring savings and satisfaction for the users.