查询词典 hidden line algorithm

a system of along-track mode sar based on the gps is established.by seeing the gps signal as a chirp,chirp scaling algorithm of this mode with large squint angle is investigated.chirp scaling algorithm is considered more efficient and widely applicable when the bistatic sar system is in side-look or small squint angle mode,but in large squint angle case,the errors caused by taylor expansion are so large that the algorithm could lose its precision.in such a case,an equivalent mono-static sar range mode which has fewer errors than taylor expansion with large squint angle is proposed to substitute the range history of bistatic sar.then bistatic sar images with large squint angles are gotten by common nonlinear cs algorithm.the effectivity of the method is verified by matlab simulation.

摘 要：建立了基于gps的顺轨sar系统模型，通过将gps信号等效为chirp信号，研究了在该模式下的大斜视角chirp scaling算法。在正侧视或小斜视情况下，cs算法具有较好的聚焦性能和广泛的适用性，但在斜视角较大的情况下，该算法将散焦而不能成像，因而提出了用等效的单基地距离模型来代替双基地距离历史的方法，解决了大斜视角情况下距离模型二阶近似误差较大的问题，并结合单基地非线性cs算法，实现了在大斜视角情况下的基于gps反射信号的双基地sar高精度成像，最后通过matlab仿真进行了验证。

RSSI-based location is a hotspot in nowadays. This paper presents RSSI-based triangle and centroid location algorithm and trilateration algorithm, and analyses the average positioning error produced by this two methods. Simulation experiments prove that triangle and centroid location algorithm can obviously improve the location accuracy compared to trilateration algorithm.

基于RSSI的定位技术是现阶段研究的热点，本文提出了基于RSSI的三角形质心定位算法和三边测量法，并对两种算法所产生的平均定位误差进行仿真分析，仿真结果表明基于RSSI的三角形质心定位算法比基于RSSI的三边测量定位算法的定位精度有较大提高。

In this algorithm, the Received Signal Strength Indicator ranging technique is employed to replace the distance measurement of one hop away from the anchor node in DV-Hop algorithm. Also a 2-D Hyperbolic algorithm is used to replace the trilateration algorithm in DV-Hop.

该算法引入接收信号强度指示器测距技术代替DV-Hop算法中到锚节点一跳距离测量并采用2-D Hyperbolic算法代替DV-Hop算法中三边测量法。

The results show that values of 1n computed with the D8 algorithm are more discrete and have rougher pattern than those computed with the MFD algorithm, and the mean values of 1n with D8 algorithm are slightly higher than those with the MFD algorithm.

结果表明：与多流向法相比，D8方法的计算值较为离散，分布曲线较粗糙，平均值略高，方差和偏态系数也较大；但是，两种方法计算的1n的分布曲线大致相似。

The results show that values of ln computed with the D8 algorithm are more discrete and have rougher pattern than those computed with the MFD algorithm, and the mean values of ln with D8 algorithm are slightly higher than those with the MFD algorithm.

结果表明：与多流向法相比，D8方法的计算值较为离散，分布曲线较粗糙，平均值略高，方差和偏态系数也较大；但是，两种方法计算的ln 的分布曲线大致相似。

Constraint-based MiniCon algorithm is proposed. This algorithm adds a step of view selection. As a result, the problems of missing query rewritings and generating redundant query rewritings in traditional MiniCon algorithm in presence of domain constraints are solved, and the accuracy and completeness of the algorithm is ensured.

该算法在传统的MiniCon算法中增加了一步视图选择，解决了传统的MiniCon算法中丢失查询重写和生成冗余查询重写的问题，保证了算法的正确性和完备性，并给出了相应的算法分析和实例分析。

The innovations of this paper as follows:(1)The topological relation model between complex spatial objects is brought forward, which represented by some composite basic 9I matrix and results in general signification.(2)Time and space integrated topological model is suggested to reason about spatio-temporal change types;(3)Sweep-line algorithm is improved, and a new little circles of polyline nodes overlapped with region method is proposed. As result, it's efficient to calculate line-line, line-region and region-region topological relations.

本文的创新之处在于提出了一种能够描述复杂对象的数学表达模型，将复杂对象间的复合拓扑关系表示成基本拓扑关系的组合，具有一定的普适意义；研究了时空拓扑关系的内涵和表达方法，说明利用时空拓扑关系可隐性地实现时空变化语义的查询；对平面扫描线法进行了改进，提出了一种新的节点微小圆求交的算法，可有效地解决线面、线线、面面拓扑关系的计算问题。

Based on the existed method for interpreting line drawings, we put forward a kind of recursive method for computer interpretation of line drawings under orthographically axonometric projection. Our method can be used to interpret to the hidden-parts-drawn and the natural line drawings.

在已有基于点与平面的相对位置关系解释线框图研究成果的基础上，提出一种计算机递归解释线框图的方法，主要针对的是正轴测投影线框图的计算机解释。

This article introduces three kinds of line cliping algorithms from the basic algorithm philosophy, the algorithm description,the algorithm steps and so on. Then it used the VC programming to realize these three algorithms on the basis of analysing the characteristics and the performance of three algorithms .

本文从算法基本思想、算法描述和算法步骤等方面介绍了三种直线段裁剪算法，在对三种算法的特点和性能进行分析的基础上，使用VC编程实现了这三种算法。

The main contribution of this thesis is that we propose a collaborative filtering recommendation algorithm based on double clustering. This approach first respectively clusters resources and users by the users rating on items, then makes a collaborative filtering recommendation based on the clustering result. The new algorithm can shorten on-line recommendation time. Then, we apply the classical formula of cosine correlation to double clustering algorithm, leaving out the standardization operation. In the end, we implement an educational resource recommender system according to the need of the actual project and the result is positive.

本文的主要意义在于，首先运用聚类技术对用户和资源分别进行聚类，然后利用聚类结果进行协同过滤推荐，由于聚类部分离线周期进行，大大缩短了在线的推荐时间；然后将经典的余弦相似性计算公式运用到双重聚类算法中，省去规范化处理操作，减少运算量；最后结合实际的需要，实现一个资源推荐系统。

The shaping method of noncircular part and the tool holder's radial motion characters in noncircular turning process are discussed in detail in the thesis.

论文详细研究了非圆零件的成型方法和加工过程中刀架的径向运动规律。

I have not really liked him,I do not like his this kind of disposition.

我没有真的喜欢他，我不喜欢他的这种性格。