在合理猜想设法验证中发展学生思维

新课程标准倡导自主发现式学习,猜想验证是自主发现学习模式中的一个重要组成部分,在培养学生自主学习能力和发展学生思维等方面具有重要作用。文章重点阐述了猜想验证在小学数学课堂中的运用,通过合理猜想设法验证活动发展学生思维,提升小学生的数学学习水平。

Methods of Validating Simulation Model and Program Design

Validating simulation model is one of the important aspects for modeling and simulation. Some methods of validating model are compared and analyzed. Several typical methods, such as TIC’s inequality coefficient, gray interconnected analysis, direct spectrum estimation, maximum entropy spectral estimation based on Burg or Marple, are chosen and programmed in C language. Some examples by using the program are given. The results show that the program is available and it is best to adopt multi methods for validating models.

Design and validation of real-time dynamic spectrum management in OFDM-based HNPLC systems

Time-varying frequency selective attenuation and colored noises are unfavorable characteristics of power line communication(PLC) channels of the low voltage networks.To overcome these disadvantages,a novel real-time dynamic spectrum management(DSM) algorithm in orthogonal frequency division multiplexing(OFDM)-based high-speed narrow-band power line communication(HNPLC) systems is proposed,and the corresponding FPGA circuit is designed and realized.Performance of the proposed DSM is validated with a large amount of network experiments under practical PLC circumstance.As the noise in each narrow subcarrier is approximately Gaussian,the proposed DSM adopts the BER/SER expression formulized via the AWGN channel to provide a handy and universal strategy for power allocation.The real-time requirement is guaranteed by choosing subcarriers in group and employing the same modulation scheme within each transmission.These measures are suitable for any modulation scheme no matter the system criterion is to maximize data rate or minimize power/BER.Algorithm design and hardware implementation of the proposed DSM are given with some flexible and efficient conversions.The DSM circuit is carried out with Xilinx KC705.Simulation and practical experiments validate that the proposed real-time DSM significantly improves system performance.

Design and Implementation of Verification Code Identification Based on Anisotropic Heat Kernel

Many websites use verification codes to prevent users from using the machine automatically to register,login,malicious vote or irrigate but it brought great burden to the enterprises involved in internet marketing as entering the verification code manually.Improving the verification code security system needs the identification method as the corresponding testing system.We propose an anisotropic heat kernel equation group which can generate a heat source scale space during the kernel evolution based on infinite heat source axiom,design a multi-step anisotropic verification code identification algorithm which includes core procedure of building anisotropic heat kernel,settingwave energy information parameters,combing outverification codccharacters and corresponding peripheral procedure of gray scaling,binarizing,denoising,normalizing,segmenting and identifying,give out the detail criterion and parameter set.Actual test show the anisotropic heat kernel identification algorithm can be used on many kinds of verification code including text characters,mathematical,Chinese,voice,3D,programming,video,advertising,it has a higher rate of 25%and 50%than neural network and context matching algorithm separately for Yahoo site,49%and 60%for Captcha site,20%and 52%for Baidu site,60%and 65%for 3DTakers site,40%,and 51%.for MDP site.

Recent Advances to Change the Standards in Designing Hulls in Waves, a Validation Using an Efficient SWENSE Level-Set Approach

This paper presents recent naval applications of the SWENSE （Spectral Wave Explicit Navier-Stokes Equations） approach implemented for the first time with high order fully unstructured schemes and an efficient level-set method to capture free surface flows around realistic hull geometries. Numerical simulations in waves and/or viscous flows still lead generally to very large CPU times because of grid requirements to ensure a good propagation of incident waves in the meshed part of the fluid domain that makes unreachable any hull design optimization process in an industrial context. Furthermore, even if the SWENSE method clearly shows promising results in an academic context in both regular and irregular waves, the most recent publications still highlight several issues that remain unresolved up to now, e.g. poor scalability, diffusive wake pattern, non-versatile structured mesh approaches and only very few validation test cases are carried out on Wigley or DTMB 5415 hulls. In order to overcome those numerical difficulties and get an in-depth validation of the method on several cases in realistic wave conditions, a two and a half years＇ research project has been achieved involving several steps, starting by a set of dedicated model test experiments later used as reference for the validation of the method. The CFD commercial code ANANASTM used and developed in this research program is presented and validated in detail. The use of high order schemes on unstructured grids in combination with these SWENSE method and level-set approach offer to the maritime industry an innovative and state of the art method to achieve unequaled accuracy, low computation time and some unique advantages such as, amongst others, the end of the numerical wave propagation problems. The results of the validation were pleasing and can be considered as acceptable in general, with some challenges remaining to the solyed. Results obtained indicate that an optimization processes in waves in realistic conditions is now affordable in an industrial context.

Magnification Ratio of Mechanical Displacement Amplifier in Sensing Device

In order to monitor deformation of high temperature components for a long time,a sensing device integrating a bridge-shaped mechanical displacement amplifier has been designed.This sensing device has higher resolution and accuracy than conventional extensometers.However,the relation between the magnification ratio and the structure size of the displacement amplifier is a bottleneck of sensing device design.Addressing this,the magnification ratio of a mechanical displacement amplifier is analytically derived based on its geometry structure.Six prototypes of the displacement amplifier made in propathene are manufactured,and an experimental system is set up to validate the accuracy of the established magnification ratio equation.Theoretical magnification ratios and experimental magnification ratios are compared and agree well,which verifies that the proposed equation is reliable.This analytical equation provides an effective design method for bridge-shaped mechanical displacement amplifiers with an expected magnification ratio.

Clinical efficacy observation of thalamic pain treated with acupuncture under the guidance of evidence-based medicine

Objective To study the feasibility of the crossover trial design and the minimal imbalance index random distribution method in the clinical small-sample-size randomized controlled trial（RCT） research of thalamic pain treated with acupuncture under the guidance of evidence-based medicine（EBM）.Methods The crossover trial design was adopted.Eleven cases with the definite diagnosis were randomized into a program-I group（6 cases,treated with acupuncture before western medicine） and a program-II group（5 cases,treated with western medicine before acupuncture） according to the minimal imbalance index method.In the statistical analysis,the groups were named as an acupuncture group and a western medicine group separately,11 cases in each one.Acupuncture was applied to Xìmén（郄门 PC 4）,Yīnxì（阴郄 HT 6）,Xuèhǎi（血海 SP 10）,etc.In the control treatment,Carbamazepine was prescribed for oral administration.Either the duration of treatment or the wash-out period was 10 days.The visual analogue scale（VAS） was adopted for the efficacy assessment.Results The total effective was 100.0%（11/11） after treatment in either group.The remarkably effective rates were 63.6%（7/11） and 36.4%（4/11） in the acupuncture group and the western medicine group separately,without statistically significant difference in comparison.Conclusion The crossover trial design and the minimal imbalance index distribution method can accomplish RCT of the clinical acupuncture and moxibustion research with the small sample size involved.They can provide the high-quality evidences for clinical acupuncture research.Acupuncture therapy can achieve the same therapeutic effect as Carbamazepine,the common western medicine,and the efficacy of it is potentially superior to that of western medicine.

Adjusting principle of gas jet controlling inlet and numerical verification

To improve the inlet performance of a ramjet working under variable conditions,a design is proposed by controlling the inlet with jet controlling,which combines the method of reducing the sealing Mach number of the external waves and the technique of controlling inlet by jet controlling.Three inlets were designed to analyze the feasibility and a numerical simulation method was used to simulate the three inlet flow fields.The adjustment mechanism of the design was studied through analysis of the simulation results.The design was verified by comparing the performances of the three inlets.The study showed that the method of reducing the sealing Mach number of the external wave system can improve the flow coefficient when the inlet works at low Mach numbers.The technique of controlling inlet by jet controlling can homogenize inlet flow fields at high Mach numbers,reduce effective throat area and increase the total pressure recovery(TPR).Adjustable inlets controlled by jet controlling demonstrate good performance at certain working ranges.