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1.
When satellite navigation receivers are equipped with multiple antennas, they can deliver attitude information. In previous researches, carrier phase differencing measurement equations were built in the earth-centered, earth-fixed （ECEF） coordinate, and attitude angles could be obtained through the rotation matrix between the body frame （BF） and the local level frame （LLF）. Different from the conventional methods, a hybrid algorithm is presented to resolve attitude parameters utilizing the single differencing （SD） carrier phase equations established in LLF. Assuming that the cycle integer ambiguity is known, the measurement equations have attitude analytical resolutions by using simultaneous single difference equations for two in-view satellites. In addition, the algorithm is capable of reducing the search integer space into countable 2D discrete points and the ambiguity function method （AFM） resolves the ambiguity function within the analytical solutions space. In the case of frequency division multiple access （FDMA） for the Russian Global Orbiting Navigation Satellite System （GLONASS）, a receiver clock bias estimation is employed to evaluate its carrier phase. An evaluating variable and a weighted factor are introduced to assess the integer ambiguity initialization. By static and dynamic ground experiments, the results show that the proposed approach is effective, with enough accuracy and low computation. It can satisfy attitude determination in cases of GPS alone and combined with GLONASS.  相似文献   

2.
Statistics teaching should not be carried out in the same way for all kinds of university students. Instead, teaching statistics should take into account the different fields of study that students have chosen. For example, students of sciences or engineering have different interests and backgrounds compared to students of any social or juridical field. The authors address this latter group of students （social, juridical, labor or even economics）. The authors propose a direct approach： beginning with a real situation or supposition with real data. Questions of interest are explored and put into the language of statistics. To answer the questions, the necessary statistical methods are used. If needed, these methods are presented and explained at that time. Finally, the authors return to the beginning, to give an interpretation of the results. The approach takes into account the students＇ levels and the kind of studies or professional orientation of these students.  相似文献   

3.
On the basis of the current sheet model, a new analytical solution for permanent magnet （PM） bearings is developed. Compared with analytical methods based on the coupling energy model and the magnetic dipole model, the proposed one is more physically intuitive and convenient for engineering designers. According to the analytical model, the thrust characteristics of a novel PM thrust bearing is studied and verified by finite element analysis （FEA）. In the proposed thrust bearing configuration, the rotor is composed of stacked PM tings with alternative axial magnetization directions, and the stator with alternative radial magnetization directions while copper rings are used to separate adjacent PM rings. A prototype PM thrust bearing with the proposed configuration is designed and fabricated. The performances of the PM thrust beating are experimentally validated. It is shown that the calculation accuracy of the presented analytical solution is satisfying.  相似文献   

4.
A comparative analysis of multi-output frontier models   总被引：1，自引：0，他引：1  
Recently, there have been more debates on the methods of measuring efficiency. The main objective of this paper is to make a sensitivity analysis for different frontier models and compare the results obtained from the different methods of estimating multi-output frontier for a specific application. The methods include stochastic distance function frontier, stochastic ray frontier, and data envelopment analysis. The stochastic frontier regressions with and without the inefficiency effects model are also compared and tested. The results indicate that there are significant correlations between the results obtained from the alternative estimation methods.  相似文献   

5.
This paper presents the results of a formative evaluation of young faculty development scholarship program conducted in teachers colleges at Chinese impoverished areas. In the paper we describe the implementation of the program, the utilization of scholarship by recipients, recipients＇ satisfaction, and outcome data. Based on these data we discuss the successes and barriers of the program thus far. Several data collection methods were used in the evaluation： a longitudinal random survey of recipients, group interviews with their students, directors and colleagues, in-person interviews with individual recipient, interviews with representatives of provider agencies, and the data base in provider agency. The findings reported in this paper are primarily from the recipients＇ survey. Key findings from the group interviews and representatives＇ interviews are also included. As a whole, the findings suggest success in terms of recipients＇ knowledge and use of advanced training, and high levels of satisfaction with individual development and the organization level. Continuing challenges to the faculty training and development program include long-standing barrier to recipients＇ involvement （e.g. low levels of networking） and resident uncertainty to retain in the colleges to take the social role that the program framed.  相似文献   

6.
周园 《海外英语》2013,(21):56-59
ESP,namely English for Specific Purposes,has become an integral part of English teaching in higher education.How ever,the majority of research on approaches in ESP teaching is focused on one specific method,which fails to generalize the de velopment of ESP teaching in China.In this thesis,recent Chinese research on approaches and methods in ESP teaching is re viewed,including those in established framework and an innovative one.The advantages and limitations of each methods are ana lyzed and the possible suggestions are made with a view to promoting the research on approaches and methods in ESP teaching in a more all-round way.  相似文献   

7.
Wind turbines（WTs） are quite expensive pieces of equipment in power industry. Maintenance and repair is a critical activity which also consumes lots of time and effort, hence making it a costly affair. Carefully planning the maintenance based upon condition of the equipment would make the process reasonable. Mostly the WTs are equipped with some kind of condition monitoring device/system, which provides the information about the device to the central data base i.e., supervisory control and data acquisition（SCADA） data base. These devices/systems make use of data processing techniques/methods in order to detect and predict faults. The information provided by condition monitoring equipments keeps on recoding in the SCADA data base. This paper dwells upon the techniques/methods/algorithms developed, to carry out diagnosis and prognosis of the faults, based upon SCADA data.Subsequently data driven approaching for SCADA data interpretation has been reviewed and an artificial intelligence（AI） based framework for fault diagnosis and prognosis of WTs using SCADA data is proposed.  相似文献   

8.
This article presents the methodology used by the Finnish Education Evaluation Council in the national evaluation of social and communication skills in vocational education and training. The evaluation concentrates on key competences such as learning-to-learn skills, communication skills, social skills and entrepreneurship （Implementation of Education and Stringfellow, 2005; Recommendation of the European Training 2010, 2004; Winterton, Delemare-Le Deist ＆ Parliament and of the Council of December 18, 2006 on key competencies for lifelong leaming, 2006）. The evaluation focuses particularly on skills required in the labour market. These competences are included in all vocational study programmes as a part of accompanying with other key competences. The authors＇ approach follows the principles of developmental and participative evaluation, applying the Common Quality Assurance Framework （CQAF） model, which has been accepted by the European Commission for the quality management and quality assurance framework for vocational education and training in Europe. Additional methods such as interview and statistical data gathering were used to acquire comprehensive data and ensure extensive participation of each partner involved has key competences. The evaluation material was collected from vocational education and training providers by sector （n=8） and by qualification （n=53）. Every sector and type of examination was included in the evaluation. The evaluation was based on a sample （n=130）. The evaluation data were collected from multiple sources by using multiple methods. The material included written self-evaluation reports by vocational education and training providers （n=130 which equals 95% of VET providers）, quantitative information, interviews organized by the National Board of Education and an evaluation seminar for providers as focus groups. Educational administrators, teachers, students, employers and workplace instructors participated in the self-evaluation of the vocational education and training establishments （multi-professional evaluation）.  相似文献   

9.
Attention-deficit/hyperactivity disorder （AD/HD） negativelly affects the cognitive and psychomotoric spheres of the pupil＇s social behavior and social adaptation. The review of many studies states that pupils with AD/HD achieve worse learning results because of insufficiently functioning cognitive processess, such as attention, （work） memory, thinking, problem solving, language, small- and large- scale motorics. Behavioral features, exhibited with AD/HD, include low-frustration tolerance, temper problems, persistence, emotional liability, depression, peer rejection, poor self-concept and poor self-esteem. Because of insufficiency of the cognitive processes, the difficulties of social behavior and social adaptation, pupils with AD/HD more often have a dysfunction of pupils＇ role that manifests by learning difficulties and behavior problems. The manifestation of the disorder in the younger school age in the context of children＇s school activities and roles actualizes the exceptional interest of the educational science in the analyzed phenomenon. The search and construction of effective means of socio-educational help for AD/HD primary class pupils should be associated with coordination and adaptation of different effective educational methodologies of different conceptual origin. In order to develop cognitive, psycho-motoric abilities and social behavior of the group of primary class pupils with AD/HD （N=22）, activities of supplementary education were organized after classes （their duration was 6 months）. During the forming experiment, original methodologies were constructed and national and foreign researchers＇ educational methodologies were adapted and tested in new, specific conditions （methods of fairy-tales, correction of cognitive behavior, graphical-logical tasks, games in the sport hall）. Even by relatively rare activities of supplementary education in a homogeneous group of children suffering from AD/HD positive changes of cognitive, psychomotoric sphere, social behavior and social adaptation were achieved.  相似文献   

10.
Quantifying social vulnerability for flood disasters of insurance company   总被引：1，自引：0，他引：1  
Social vulnerability assessments are largely ignored when compared with biophysical vulnerability assessments. This is mainly due to the fact that there are more difficulties in quantifying them. Aiming at several pitfalls still existing in the Hoovering approach which is widely accepted, a suitable modified model is provided. In this modified model, the integrated vulnerability is made an analogy to the elasticity coefficient of a spring, and an objective evaluation criterion is established. With the evaluation criterion, the assessment indicators of social vulnerability are filtered and their weight assignments are accomplished. There is an application in the city of Changsha where floods occur often. With the relative data from the PICC Hunan Province Branch, a generalized regression neural network model is established in Matlab 7.0 and used to evaluate a company's flood social vulnerability index (SoVI). The results show that the average flood social vulnerability in Yuhua district is the highest, while Yuelu district is the lowest. It is good for disaster risk management and decision-making of insurance companies.  相似文献   

11.
This paper deals with the estimation of crest settlement in a concrete face rockfill dam （CFRD）, utilizing intelligent methods. Following completion of dam construction, considerable movements of the crest and the body of the dam can develop during the first impoundment of the reservoir. Although there is vast experience worldwide in CFRD design and construction, few accurate experimental relationships are available to predict the settlement in CFRD. The goal is to advance the development of intelligent methods to estimate the subsidence of dams at the design stage. Due to dam zonifieation and uncertainties in material properties, these methods appear to be the appropriate choice. In this study, the crest settlement behavior of CFRDs is analyzed based on compiled data of 24 CFRDs constructed during recent years around the world, along with the utilization of gene ex- pression programming （GEP） and adaptive neuro-fuzzy inference system （ANFIS） methods. In addition, dam height （H）, shape factor （St）, and time （t, time after first operation） are also assessed, being considered major factors in predicting the settlement behavior. From the relationships proposed, the values ofR2 for both equations of GEP （with and without constant） were 0.9603 and 0.9734, and for the three approaches of ANFIS （grid partitioning （GP）, subtractive clustering method （SCM）, and fuzzy c-means clustering （FCM）） were 0.9693, 0.8657, and 0.8848, respectively. The obtained results indicate that the overall behavior evaluated by this approach is consistent with the measured data of other CFRDs.  相似文献   

12.
In order to model the movement progress in case of risks such as dam collapse and coastal inundation, particle-based simulation methods, including the discrete-element method and smoothed particle hydrodynamics, which have specific advantages in modeling complex three-dimensional environmental fluid and particulate flows, are adopted as an effective way to illustrate environmental applications possibly happening in the real world. The theory of these methods and their relative advantages compared with traditional methods are discussed. Examples of 3-D flows on realistic topography including the flooding of a river valley as a result of a dam collapse and coastal inundation by a tsunami are introduced. Issues related to validation and quality data availability are also discussed. The results show that the simulations provide a valuable insight in a given situation for the security management of reservoir dams. Validation can only be performed where both the initial and final states can be very well characterized.  相似文献   

13.
Slip and deformation of concrete sandwich panels under uniformly distributed loads is concerned. The effect of slip on the deformation of concrete sandwich panels are studied,and the analytical expressions of slip and deformation for concrete sandwich panels is obtained. These formulae can describe the slip distribution and account for its effect on deformation. In order to restrict the bound of formula, the formula of crack moment is obtained. The results of theoretical calculation are compared with those of tests and finite element methods. The comparison shows that the results of theoretical calculation are in accord with those of tests and finite element methods. So the theoretical calculation can be used to calculate slip and deformation of concrete sandwich panels in practical projects.  相似文献   

14.
We present novel vector permutation and branch reduction methods to minimize the number of execution cycles for bit reversal algorithms. The new methods are applied to single instruction multiple data （SIMD） parallel implementation of complex data floating-point fast Fourier transform （FFT）. The number of operational clock cycles can be reduced by an average factor of 3.5 by using our vector permutation methods and by 1.1 by using our branch reduction methods, compared with conventional implementations. Experiments on MPC7448 （a well-known SIMD reduced instruction set computing processor） demonstrate that our optimal bit-reversal algorithm consistently takes fewer than two cycles per element in complex array operations.  相似文献   

15.
This study compares the ability of different robust regression estimators to detect and classify outliers. Well-known estimators with high breakdown points were compared using simulated data. Mean success rates （MSR） were computed and used as comparison criteria. The results showed that the least median of squares （LMS） and least trimmed squares （LTS） were the most successful methods for data that included leverage points, masking and swamping effects or critical and concentrated outliers. We recommend using LMS and LTS as diagnostic tools to classify outliers, because they remain robust even when applied to models that are heavily contaminated or that have a complicated structure of outliers.  相似文献   

16.
We propose a medium access control （MAC） protocol for uplink transmissions in wireless local area networks （WLANs）, where both stations and access points （APs） are equipped with multiple antennas. The protocol solves some common problems in utilizing multiple input multiple output （MIMO） under the 802.11 protocol, e.g., how to deploy preamble （training sequence） used for channel estimation and how to enable simultaneous data transmissions, and facilitates two simultaneous uplink data transmissions via a cross-layer approach. Furthermore, we develop a 3D discrete-time Markov model to analyze the performance of the proposed WLAN scheme. The analytical results are verified by simulation, and numerical results show that the system throughput can be significantly improved by our proposed scheme as compared with conventional schemes.  相似文献   

17.
This work describes the genesis, articulation and consolidation from 2007 of a social network of b-learning （blended learning） in the UA （University of Alicante） （Spain）, with the institutional backing of the Office of the Vice President for Education Technology and Innovation, and the momentum and advice of professor Angel Fidalgo （UNESCO （United Nations Educational, Scientific and Cultural Organization） chair for University of Management and Policy）. The social network currently has more than 25 teachers, working on different work linkages with the university, implementing or intending to apply the teaching methodologyb-learning during the course 2007-2008 in a variety of courses and degrees. To do so, several resource centers （blogs, wikis, Wimba Create （before CourseGenie）, etc.）, and digital platforms （Virtual Campus of the UA, Moodle, etc.） are used.  相似文献   

18.
Attribute reduction is necessary in decision making system. Selecting right attribute reduction method is more important. This paper studies the reduction effects of principal components analysis （PCA） and system reconstruction analysis , SRA） on coronary heart disease data. The data set contains 1723 records, and 71 attributes in each record. PCA and SRA are used to reduce attributes number （less than 71 ） in the data set. And then decision tree algorithms. C4.5, classification and regression tree （ CART）, and chi-square automatic interaction detector （ CHAID ）, are adopted to analyze the raw data and attribute reduced data. The parameters of decision tree algorithms, including internal node number, maximum tree depth, leaves number, and correction rate are analyzed. The result indicates that. PCA and SRA data can complete attribute reduction work. and the decision-making rate on the reduced data is quicker than that on the raw data： the reduction effect of PCA is better than that of SRA. while the attribute assertion of SRA is better than that of PCA. PCA and SRA methods exhibit good performance in selecting and reducing attributes.  相似文献   

19.
This study examines the relation between the social adjustment in the classroom and the role of aggressor or victim, in school violence situations. Participants were 1,635 students （aged 14-18 years old）, from a representative sample, with different levels （compulsory secondary education, specific/initial training courses and vocational programs）. Students filled out a questionnaire that included measures of types of violence （exclusion, verbal violence, physical violence）, from the point of view of the three roles that are implicated （aggressors, victims and observants）, and a sociometric questionnaire. The variables measured were： frequency of school violence （exclusion, psychological violence and physical violence） and the peer status （rejected, controversial, neglected, average or popular）. The statistic analyses used were χ^2- and F- tests. From the results we can point out the importance of these variables in the school violence situations. The implications of these findings and the relevance for preventive programs are discussed.  相似文献   

20.
Information and communication are important elements in the growth of societies; they determine the characteristics of the societies. Multipurpose Community Access Points as the lowest locus of the information receiving and transmitting, data storage and retrieval, and also as the locus for the basic interaction among members of the community will presume to contribute a lot to community development especially to improve the quality of life as the whole. E - Learning is a process of transfer of Information （knowledge）, in the sense of science, and values （social, cultural, ethical and moral values）. E-government is an application of ICT to enhance government administration. Its contents may be very complex, but it is meant to enhance public services. Due to the social and cultural implications ICT is also said as civilizing. The use of ICTs has social, economic and cultural implications to reach civil society.  相似文献   

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