期刊文献+
共找到3,023篇文章
< 1 2 152 >
每页显示 20 50 100
Modeling Rice rgMT as a Plant Metallothionein-Like Protein by the Distance Geometry and Homology Methods
1
作者 吕暾 刘进元 +1 位作者 张日清 赵南明 《Acta Botanica Sinica》 CSCD 2003年第11期1297-1306,共10页
Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in th... Rice metallothionein-like protein (rgMT) shows characteristics of a three-section pattern composed of two highly conserved cysteine rich (CR) domains in the terminals and a spacer without cysteine (cys) residues in the center of the molecule. In this paper, the two CR domains and the spacer region were modeled by the distance geometry and homology methods separately. For the CR domains, twenty random models were generated for each cys combination based on the constraint conditions of CXC (C represents cys, X represents any amino acid other than cys), and CXXC motifs and a metal-sulfur chelating cluster. Four models for the N-terminal and two for C-terminal CR domain containing metal chelating structures formed by different combinations of cys were selected from 900 possible conformations. The GOR method was used to predict the secondary structure of the spacer region and its model was built by the homology method. After three parts of the protein were modeled, they were connected to form a three-dimensional structure model of rgMT. The whole conformation showed that rgMT could form two independent metal-sulfur chelating structures connected by a spacer peptide, without a structural or energy barrier for them to form two independent metal-chelating clusters just as mammalian metallothionein (MT) proteins. As all plant metallothionein-like (MT-L) proteins have the same primary structural characteristic, two CR domains connected by a spacer region, and many have the same cys arrangement pattern as rgMT, the three-dimensional structure model of rgMT will provide an important reference for the structural study of other plant MT-L proteins. 展开更多
关键词 distance geometry homology method rice metallothionein-like protein structural modeling
下载PDF
Initial support distance of a non-circular tunnel based on convergence constraint method and integral failure criteria of rock 被引量:8
2
作者 AN Xue-xu HU Zhi-ping +3 位作者 SU Yan CAO Shuang-li TAO Lei ZHANG Yong-hui 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第11期3732-3744,共13页
For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initi... For deep tunnel projects,selecting an appropriate initial support distance is critical to improving the self-supporting capacity of surrounding rock.In this work,an intuitive method for determining the tunnel’s initial support distance was proposed.First,based on the convergence-confinement method,a three-dimensional analytical model was constructed by combining an analytical solution of a non-circular tunnel with the Tecplot software.Then,according to the integral failure criteria of rock,the failure tendency coefficients of hard surrounding rock were computed and the spatial distribution plots of that were constructed.On this basis,the tunnel’s key failure positions were identified,and the relationship between the failure tendency coefficient at key failure positions and their distances from the working face was established.Finally,the distance from the working face that corresponds to the critical failure tendency coefficient was taken as the optimal support distance.A practical project was used as an example,and a reasonable initial support distance was successfully determined by applying the developed method.Moreover,it is found that the stability of hard surrounding rock decreases rapidly within the range of 1.0D(D is the tunnel diameter)from the working face,and tends to be stable outside the range of 1.0D. 展开更多
关键词 tunnel engineering convergence confinement method integral failure criteria of rock non-circular tunnel initial supporting distance
下载PDF
Fuzzy distances based FMAGDM compromise ratio method and application 被引量:2
3
作者 Zhenfeng Rui Dengfeng Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第3期455-460,共6页
An extended compromise ratio method(CRM) based on fuzzy distances is developed to solve fuzzy multi-attribute group decision making problems in which weights of attributes and ratings of alternatives on attributes a... An extended compromise ratio method(CRM) based on fuzzy distances is developed to solve fuzzy multi-attribute group decision making problems in which weights of attributes and ratings of alternatives on attributes are expressed with values of linguistic variables parameterized using triangular fuzzy numbers.A compromise solution is determined by introducing the ranking index based on the concept that the chosen alternative should be as close as possible to the positive ideal solution and as far away from the negative ideal solution as possible simultaneously.This proposed method is compared with other existing methods to show its feasibility and effectiveness and illustrated with an example of the military route selection problem as one of the possible applications. 展开更多
关键词 fuzzy multi-attribute group decision making(FMAGDM) compromise ratio method(CRM) linguistic variable fuzzy number fuzzy distance.
下载PDF
Ranking Method for Complementary Judgment Matrixes with Fuzzy Numbers Based on Hausdorff Metric Distance 被引量:1
4
作者 侯福均 吴祈宗 《Journal of Beijing Institute of Technology》 EI CAS 2005年第4期458-461,共4页
A method for ranking complementary judgment matrixes with traspezoidal fuzzy numbers based on Hausdorff metric distance and fuzzy compromise decision approach is proposed. With regard to fuzzy number complementary jud... A method for ranking complementary judgment matrixes with traspezoidal fuzzy numbers based on Hausdorff metric distance and fuzzy compromise decision approach is proposed. With regard to fuzzy number complementary judgment matrixes given by a decider group whose members have various weights, the expert's information was aggregated first by means of simple weight average(SWA) method and Bonissone calculational method. Hence a matrix including all the experts' preference information was got. Then the matrix' column members were added up and the fuzzy evaluation values of the alternatives were got. Lastly, the Hausdorff metric distance and fuzzy compromise decision approach were used to rank the fuzzy evaluation values and then the ranking values of all the alternatives were got. Because exact numbers and triangular fuzzy numbers could all be transformed into trapezoidal fuzzy numbers, the method developed can rank complementary judgment matrixes with trapezoidal fuzzy numbers, triangular fuzzy numbers and exact numbers as well. An illustrative example is also given to verify the developed method and to demonstrate its feasibility and practicality. 展开更多
关键词 complementary judgment matrix trapezoidal fuzzy number Bonissone calculational method fuzzy compromise decision approach Hausdorff metric distance
下载PDF
A method for computing unsupported roof distance in roadway advancement and its in-situ application 被引量:2
5
作者 Chen Yong Bai Jianbiao +2 位作者 Yan Shuai Hao Shengpeng Dao Viet Doan 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2016年第4期551-556,共6页
A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the ... A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month. 展开更多
关键词 Unsupported roof distance (URD)Roadway advancement Difference method Roof stress Drivage per cycle Unsupported roof distance test
下载PDF
The Method of Calculating Average Skidding Distance
6
作者 张志贤 冯志丽 《Journal of Forestry Research》 SCIE CAS CSCD 1997年第1期47-49,共3页
By analyzing the existing average skidding distance formulac and the shape of the landing area, theauthors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and th... By analyzing the existing average skidding distance formulac and the shape of the landing area, theauthors put forward that the average skidding distance is the shortest when the ratio of length and width is 1, and the landing collectioll area is in proportion to of average geometrical skidding distance. The new models of calculating average distance are presented. 展开更多
关键词 AVERAGE distance CALCULATION method Loggingarea
下载PDF
A method for extracting anomaly map of Au and As using combination of U-statistic and Euclidean distance methods in Susanvar district,Iran
7
作者 Seyyed Saeed Ghannadpour Ardeshir Hezarkhani Mostafa Sharifzadeh 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第11期2693-2704,共12页
Quantitative descriptions of geochemical patterns and providing geochemical anomaly map are important in applied geochemistry. Several statistical methodologies are presented in order to identify and separate geochemi... Quantitative descriptions of geochemical patterns and providing geochemical anomaly map are important in applied geochemistry. Several statistical methodologies are presented in order to identify and separate geochemical anomalies. The U-statistic method is one of the most important structural methods and is a kind of weighted mean that surrounding points of samples are considered in U value determination. However, it is able to separate the different anomalies based on only one variable. The main aim of the presented study is development of this method in a multivariate mode. For this purpose, U-statistic method should be combined with a multivariate method which devotes a new value to each sample based on several variables. Therefore, at the first step, the optimum p is calculated in p-norm distance and then U-statistic method is applied on p-norm distance values of the samples because p-norm distance is calculated based on several variables. This method is a combination of efficient U-statistic method and p-norm distance and is used for the first time in this research. Results show that p-norm distance of p=2(Euclidean distance) in the case of a fact that Au and As can be considered optimized p-norm distance with the lowest error. The samples indicated by the combination of these methods as anomalous are more regular, less dispersed and more accurate than using just the U-statistic or other nonstructural methods such as Mahalanobis distance. Also it was observed that the combination results are closely associated with the defined Au ore indication within the studied area. Finally, univariate and bivariate geochemical anomaly maps are provided for Au and As, which have been respectively prepared using U-statistic and its combination with Euclidean distance method. 展开更多
关键词 mineral ANOMALY Susanvar DISTRICT U-STATISTIC method Euclidean distance BIVARIATE ANOMALY MAP
下载PDF
LEVEL SET METHODS BASED ON DISTANCE FUNCTION
8
作者 王德军 唐云 +1 位作者 于洪川 唐泽圣 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第8期950-960,共11页
Some basic problems on the level set methods were discussed, such as the method used to preserve the distance junction , the existence and uniqueness of solution for the level set equations. The main contribution is t... Some basic problems on the level set methods were discussed, such as the method used to preserve the distance junction , the existence and uniqueness of solution for the level set equations. The main contribution is to prove that in a neighborhood of the initial zero level set, the level set equations with the restriction of the distance function have a unique solution, which must be the signed distance function with respect to the evolving surface. Some skillful approaches were used: Noticing that any solution for the original equation was a distance function, the original level set equations were transformed into a simpler alternative form. Moreover, since the new system was not a classical one, the system was transformed into an ordinary one, for which the implicit function method was adopted. 展开更多
关键词 level set methods distance function existence and uniqueness of the solution
下载PDF
Generalized Minimum Perpendicular Distance Square Method of Estimation
9
作者 Rezaul Karim Morshed Alam +1 位作者 M. M. H. Chowdhury Forhad Hossain 《Applied Mathematics》 2012年第12期1945-1949,共5页
In case of heteroscedasticity, a Generalized Minimum Perpendicular Distance Square (GMPDS) method has been suggested instead of traditionally used Generalized Least Square (GLS) method to fit a regression line, with a... In case of heteroscedasticity, a Generalized Minimum Perpendicular Distance Square (GMPDS) method has been suggested instead of traditionally used Generalized Least Square (GLS) method to fit a regression line, with an aim to get a better fitted regression line, so that the estimated line will be closest one to the observed points. Mathematical form of the estimator for the parameters has been presented. A logical argument behind the relationship between the slopes of the lines and has been placed. 展开更多
关键词 HETEROSCEDASTICITY Ordinary Least SQUARE method Minimum PERPENDICULAR distance SQUARE method GENERALIZED Least SQUARE method
下载PDF
Study of Lightning Safety Distance Using Rolling Sphere Method
10
作者 Nor Zaihar Yahaya Mohd Akhmal Daud 《Energy and Power Engineering》 2013年第3期266-273,共8页
The development of a computer program for evaluation of lightning safety distance between the tower and satellite dish is written in M-File MATLAB. The 3-dimensional illustrative graphics model is used to capture bett... The development of a computer program for evaluation of lightning safety distance between the tower and satellite dish is written in M-File MATLAB. The 3-dimensional illustrative graphics model is used to capture better understanding on how lightning protection system (LPS) works. The study of physical length of grounding electrode used on the tower is found to be significantly affecting the grounding system performances where they depend on magnitude of dispersed lightning strikes current and the settling time for the current to completely disperse. The grounding system performance is studied by using lightning impulse current (LIC) generator, simulated in OrCad PSpice software. It is found that the optimum length of vertical lightning rod in LPS is the same with the striking distance. There is no significant improvement is observed in lightning safety distance if the length of vertical lightning rod is higher than striking distance. The lightning strike peak current that has larger magnitude than the withstanding insulation level of specified object causes no physical damage. It is because the lightning safety distance increases when the lightning strike peak current becomes higher. It is also found that the lower grounding impedance generates higher magnitude of dispersed peak current and faster settling time. 展开更多
关键词 LIGHTNING Protection System (LPS) ROLLING SPHERE method (RSM) Striking distance
下载PDF
An Improved Minimum Distance Method Based on Artificial Neural Networks
11
作者 Qing Li, Deling Zheng, Wenbo Meng Yong Tang Information Engineering School, University of Science and Technology Beijing, Beijing 100083, China E-mail: Li_Qing_2001@263.net 《Journal of University of Science and Technology Beijing》 CSCD 2002年第1期74-77,共4页
MDM (minimum distance method) is a very popular algorithm in staterecognition. But it has a presupposition, that is, the distance within one class must be shorterenough than the distance between classes. When this pre... MDM (minimum distance method) is a very popular algorithm in staterecognition. But it has a presupposition, that is, the distance within one class must be shorterenough than the distance between classes. When this presupposition is not satisfied, the method isno longer valid. In order to overcome the shortcomings of MDM, an improved minimum distance method(IMDM) based on ANN (artificial neural networks) is presented. The simulation results demonstratethat IMDM has two advantages, that is, the rate of recognition is faster and the accuracy ofrecognition is higher compared with MDM. 展开更多
关键词 state recognition minimum distance method artificial neural networks
下载PDF
On the Computing of the Minimum Distance of Linear Block Codes by Heuristic Methods
12
作者 Mohamed Askali Ahmed Azouaoui +1 位作者 Said Nouh Mostafa Belkasmi 《International Journal of Communications, Network and System Sciences》 2012年第11期774-784,共11页
The evaluation of the minimum distance of linear block codes remains an open problem in coding theory, and it is not easy to determine its true value by classical methods, for this reason the problem has been solved i... The evaluation of the minimum distance of linear block codes remains an open problem in coding theory, and it is not easy to determine its true value by classical methods, for this reason the problem has been solved in the literature with heuristic techniques such as genetic algorithms and local search algorithms. In this paper we propose two approaches to attack the hardness of this problem. The first approach is based on genetic algorithms and it yield to good results comparing to another work based also on genetic algorithms. The second approach is based on a new randomized algorithm which we call 'Multiple Impulse Method (MIM)', where the principle is to search codewords locally around the all-zero codeword perturbed by a minimum level of noise, anticipating that the resultant nearest nonzero codewords will most likely contain the minimum Hamming-weight codeword whose Hamming weight is equal to the minimum distance of the linear code. 展开更多
关键词 Minimum distance Error Impulse method Heuristic methods Genetic Algorithms NP-HARDNESS Linear Error Correcting Codes BCH Codes QR Codes Double Circulant Codes
下载PDF
Comparison of Analyses of Genetic Structure among Chinese Indigenous Chicken Breeds using Distance-based and Model-based Methods
13
作者 LI Hui-fang CHEN Kuan-wei +5 位作者 HAN Wei ZHANG Xue-yu GAO Yu-shi CHEN Guo-hong ZHU Yun-fen WANG Qiang 《畜牧兽医学报》 CAS CSCD 北大核心 2009年第S1期8-12,共5页
The Nei's improved genetic distance(DA)and gene flow(Nm)were measured using sixteen microsatellite markers.Dendograms based on DA genetic distance using the neighbor-joining(NJ)method and STRUCTURE program were co... The Nei's improved genetic distance(DA)and gene flow(Nm)were measured using sixteen microsatellite markers.Dendograms based on DA genetic distance using the neighbor-joining(NJ)method and STRUCTURE program were constructed to analyze the genetic structure and relationship among 10 Chinese indigenous chicken breeds.The results showed that dendograms of DA genetic distance using the NJ method divided the 10 chicken breeds into two main clusters;one consisted of breeds of low weight body(CHA,TTB,XIA,GUS and BAI),the other contained heavier breeds(LAN,DAG,YOU,XIS and LUY).In the lighter breeds,TIB and CHA clustered together,as did XIA and GUS.In the heavier breeds,XIS and LUY was clustered together in one branch,but LAN,DAG and YOU clustered in independent branches.The results were consistent with Nm estimates among the 10 indigenous chicken breeds.The STRUCTURE program properly inferred the presence of genetic structure despite not pre-defining the origin of individuals.The genetic cluster inferred by STRUCTURE was basically the same as that from the DA distance clustering method.An advantage of the STRUCTURE program was its ability to identify the migrants and admixed individuals in the 10 chicken populations;this could not be achieved by use of the DA distance clustering method. 展开更多
关键词 microsatellite CHINESE chicken BREEDS distance-based CLUSTERING method MODEL-BASED CLUSTERING method
下载PDF
Research on Simulation of Langlie Method Test of Fuze Arming Distance
14
作者 闻泉 王雨时 《Defence Technology(防务技术)》 SCIE EI CAS 2009年第3期221-227,共7页
In mathematically statistical test methods that were used to get arming distance of fuze,Langlie method has been widely applied because it only use a few samples. Monte-Carlo method was used to simulate and calculate ... In mathematically statistical test methods that were used to get arming distance of fuze,Langlie method has been widely applied because it only use a few samples. Monte-Carlo method was used to simulate and calculate Langlie method test of fuze arming distance by using computer. The result shows that the larger error and scatter exist in the estimate of arming distance variance although 50% response level of arming distance can be estimated using a little sample; the correction coefficient of variance estimate can be got by simulating and calculating,but it is useless to a certain single test; this means that a larger error exists when Langlie method test is used to get the muzzle safety distance and the arming distance of fuze,and the maximum arming distance becomes shorter and the minimum one longer without correcting. 展开更多
关键词 距离模拟 炮口保险 引信 方法试验 蒙特卡罗方法 方差估计 统计测试 计算机
下载PDF
Application of Weighted Average Method in Evaluation System for Rural Cadre Distance Education
15
作者 DAI Li-na1,ZHENG Bo-wei1,DONG Hai-ge2 1.Institute of Agricultural Scientech Information,Beijing Academy of Agriculture and Forestry Sciences,Beijing 100097,China 2.Food Quality Supervision and Management Section,Chaoyang Branch of Beijing Administration for Industry and Commerce,Beijing 100125,China 《Asian Agricultural Research》 2012年第3期66-68,共3页
We elaborate the application method,process and effect of weighted average method in the examination and evaluation system for modern distance education of rural party members and cadres.The study shows that this meth... We elaborate the application method,process and effect of weighted average method in the examination and evaluation system for modern distance education of rural party members and cadres.The study shows that this method reflects the evaluation results objectively and comprehensively and plays a remarkable role in establishing and improving the examination and evaluation system,thus will have an important reference value for the development of modern distance education of rural party members and cadres in the future. 展开更多
关键词 RURAL MODERN distance education WEIGHTED AVERAGE m
下载PDF
Assessment of different genetic distances in constructing cotton core subset by genotypic values 被引量:7
16
作者 Jian-cheng WANG Jin HU +1 位作者 Xin-xian HUANG Sheng-chun XU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2008年第5期356-362,共7页
One hundred and sixty-eight genotypes of cotton from the same growing region were used as a germplasm group to study the validity of different genetic distances in constructing cotton core subset. Mixed linear model a... One hundred and sixty-eight genotypes of cotton from the same growing region were used as a germplasm group to study the validity of different genetic distances in constructing cotton core subset. Mixed linear model approach was employed to unbiasedly predict genotypic values of 20 traits for eliminating the environmental effect. Six commonly used genetic distances(Euclidean,standardized Euclidean,Mahalanobis,city block,cosine and correlation distances) combining four commonly used hierarchical cluster methods(single distance,complete distance,unweighted pair-group average and Ward's methods) were used in the least distance stepwise sampling(LDSS) method for constructing different core subsets. The analyses of variance(ANOVA) of different evaluating parameters showed that the validities of cosine and correlation distances were inferior to those of Euclidean,standardized Euclidean,Mahalanobis and city block distances. Standardized Euclidean distance was slightly more effective than Euclidean,Mahalanobis and city block distances. The principal analysis validated standardized Euclidean distance in the course of constructing practical core subsets. The covariance matrix of accessions might be ill-conditioned when Mahalanobis distance was used to calculate genetic distance at low sampling percentages,which led to bias in small-sized core subset construction. The standardized Euclidean distance is recommended in core subset construction with LDSS method. 展开更多
关键词 Core subset Mixed linear model Least distance stepwise sampling (LDSS) method Standardized Euclidean distance Mahalanobis distance
下载PDF
Role of Parallel Tempering Monte Carlo Simulation in 2D Ising Spin Glass System with Distance Dependent Interaction 被引量:1
17
作者 Habte Dulla Berry Pooran Singh 《Journal of Physical Science and Application》 2012年第7期216-223,共8页
Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers. Therefore, parallel tempering Monte Carlo simulation was used in order to get fast thermalisation (to min... Spin glass system is a complex disordered system with a number of local minima separated by entropic barriers. Therefore, parallel tempering Monte Carlo simulation was used in order to get fast thermalisation (to minimize the relaxation time). Distance dependent interaction coupling in 2D is studied in order to show how a spin glass phase transition occurs when couplings between far away spins are permitted by considering Edwards-Anderson Ising spin glass model. The interaction coupling is a quenched random variable whose probability of being non-zero decays with distance between two spin sites rij = |i-j|mod(L/2).The interaction coupling is random and its probability distribution is decaying with the distance between the spins (p(Jij) αrij^-ρ). The model is studied by changing p among three different regimes (p 〉 2D, 4/3 D〈 p 〈 2D, p 〈 4/3D). A phase transition temperature for p = 2, 3, 4 is obtained. 展开更多
关键词 Parallel tempering Monte Carlo method thermalisation spin glass system distance dependent interaction coupling andphase transition.
下载PDF
Are Type Ia Supernovae Reliable Distance Indicators?
18
作者 Lian-Zhong Lü Yi-Ping Qin Fu-Wen Zhang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2007年第5期649-656,共8页
Recent applications of type Ia supernovae (SNe Ia) in cosmology have successfully revealed the accelerating expansion of the universe. However, as distance indicators used in measuring the expansion history of the u... Recent applications of type Ia supernovae (SNe Ia) in cosmology have successfully revealed the accelerating expansion of the universe. However, as distance indicators used in measuring the expansion history of the universe and probing the nature of dark energy, these objects must pass more strict tests. We propose a K-S test to investigate if there exists any systematic bias when deriving the luminosity distances under the standard candle assumption. Two samples, one comprising 71 high-redshift SNe Ia and the other, 44 nearby ones, are used in our investigation. We find that it is likely there exists a bias in the adopted samples, which is probably caused by a systematic error, e.g. in the color parameter used in the luminosity calibration and a bias may be caused by the SN evolution or by varying properties of the dust surrounding the SNe Ia. 展开更多
关键词 COSMOLOGY observations -- distance scale -- galaxies distances and redshifts -- methods statistical -- supernovae general
下载PDF
Distribution of Miss Distance for Pursuit-Evasion Problem
19
作者 Shengwen Xiang Hongqi Fan Qiang Fu 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2020年第4期1161-1168,共8页
Miss distance is a critical parameter of assessing the performance for highly maneuvering targets interception(HMTI). In a realistic terminal guidance system, the control of pursuer depends on the estimate of unknown ... Miss distance is a critical parameter of assessing the performance for highly maneuvering targets interception(HMTI). In a realistic terminal guidance system, the control of pursuer depends on the estimate of unknown state, thus the miss distance becomes a random variable with a prior unknown distribution. Currently, such a distribution is mainly evaluated by the method of Monte Carlo simulation. In this paper, by integrating the estimation error model of zero-effort miss distance(ZEM) obtained by our previous work, an analytic method for solving the distribution of miss distance is proposed, in which the system is presumed to use a bang-bang control strategy. By comparing with the results of Monte Carlo simulations under four different types of disturbances(maneuvers), the correctness of the proposed method is validated. Results of this paper provide a powerful tool for the design, analysis and performance evaluation of guidance system. 展开更多
关键词 Analytical method bang-bang strategy miss distance distribution pursuit-evasion problem
下载PDF
Facility Location Decisions Based on Driving Distances on Spherical Surface
20
作者 Han Shih 《American Journal of Operations Research》 2015年第5期450-492,共43页
Facility location problems are concerned with the location of one or more facilities in a way that optimizes a certain objective such as minimizing transportation cost, providing equitable service to customers, captur... Facility location problems are concerned with the location of one or more facilities in a way that optimizes a certain objective such as minimizing transportation cost, providing equitable service to customers, capturing the largest market share, etc. Many facility location decisions involving distance objective functions on Spherical Surface have been approached using algorithmic, metaheuristic algorithms, branch-and-bound algorithm, approximation algorithms, simulation, heuristic techniques, and decomposition method. These approaches are most based on Euclidean distance or Great circle distance functions. However, if the location points are widely separated, the difference between driving distance, Euclidean distance and Great circle distance may be significant and this may lead to significant variations in the locations of the corresponding optimal source points. This paper presents a framework and algorithm to use driving distances on spherical surface and explores its use as a facility location decision tool and helps companies assess the optimal locations of facilities. 展开更多
关键词 FACILITY LOCATION SPHERICAL Surface Euclidean distance GREAT Circle distance Clustering HEURISTIC method
下载PDF
上一页 1 2 152 下一页 到第
使用帮助 返回顶部