投影

This paper investigates the converse theorem of rectangular projection theorem in descriptive geometry,and furthermore supplements and confirms another converse theorem,If the projection of two lines intersecting vertically fo rms a rectangle on a certain projecting plane,at least one line of the two lines is parallel to the projecting plane.

通过对《画法几何学》中直角投影定理的逆定理的研究，得出："若垂直相交的两直线在某一投影面上投影成直角，则该两直线至少有一条直线平行于该投影面"的推论。

This article used the truncation mark law to discuss the common quadratic surface on the coordinate plane projection, based on this gave by the surface encircles three-dimensional asks the law on the coordinate plane projection one kind, this kind asked method the superiority lay in does not draw the range of integration graph also to be able to determine it on the coordinate plane projection.

本文利用截痕法讨论了常见二次曲面的在坐标面上的投影，在此基础上给出由曲面所围立体在坐标面上的投影的一种求法，这种求法的优越性在于不画出积分区域图形也能确定它在坐标面上的投影。最后以实例说明这种求投影的方法在计算三重积分中的应用。

According to the principle of the diameter of a circle corresponding to the right angle and the principle of short side for little angle in right triangle, projecting the initially-chosen point to the hyper-planes of the linear equation group in which every linear equation can be regarded as a hyper-plane and the projection points can be obtained. The initially-chosen point, and one arbitrary projection point, and the solution point are all on the surface of the relative hyper-geometry ball, therein-to, there is a projection point which is nearest to the solution point and it can be regarded as the next iterative initially-chosen point, so the solution problem of the linear equation group can be changed as an iterative problem of approaching the solution on the surface of a hyper-geometry ball.

根据直径对应的圆周角足直角以及直角三角形中短边对小角的原理进一步知道，当将初始点向线性方程组中各个方程所代表的超平面上投影得到投影点时，初始点和其任何一个投影点及方程组的解点都将位于一个相应的超球面上，其中必定存在一个投影点离问题解点的距离最短，即把该点作为下一次迭代的初始点，从而可将线性方程组求解的问题变成球面上逼近解点的迭代问题。

After being reflected by the object,the projection slit is imaged on a detection double slit through another lens.

准直激光束照明的投影狭缝由一个透镜以掠入射角度投影在被测物体上，狭缝投影经过被测物体表面的反射和另一个透镜的成像在探测双缝上形成投影狭缝像。

A projection slit is illuminated by a collimated laser beam.The projection slit is projected onto an object to be measured with grazing incidence through a lens.After being reflected by the object,the projection slit is imaged on a detection double slit through another lens.

准直激光束照明的投影狭缝由一个透镜以掠入射角度投影在被测物体上，狭缝投影经过被测物体表面的反射和另一个透镜的成像在探测双缝上形成投影狭缝像。

This paper systematically states the basic concept of map projection,the map projection transformation,the Gauss zone dividing porjection.

系统阐述了地图投影、地图投影变换、高斯投影及其分带投影的基本原理。

Furthermore the computer implementation process and some key topics including map projection system, map projection parameters, algorithm optimization and error computation and control in the transformation process are discussed in this paper.

以此为基础，具体探讨了地图投影变换计算机实现的主要过程，讨论了地图投影体系、投影参数、算法优化和误差控制等投影变换计算机实现中的关键问题

You can almost say that the "opposite" of the Plate Carree is the Mercator projection which stretches areas close to the poles in the opposite direction, making them look very big.

这种投影造成了严重的地图变形，使两极方向的面积被压扁了。墨卡托投影可以认为是这种投影的反面，因为墨卡托投影下两极方向的面积被放大了。

In order to solve the problem of chart projection transformation among all projections in shiphandling simulator,using the theory of power series spreading out and the method of trigonometric power series calculating back, a direct and reverse solving algorithm models of meridian arc length , and Gauss projection and Mercator projection transforming algorithm are introduced in this paper.

为了解决船舶操纵模拟器中不同投影方式海图的投影变换问题，应用幂级数展开理论和三角级数回求方法，给出了子午线弧长、等量纬度的直接正反解算法模型及高斯投影与墨卡托投影的相互转化算法。这些算法具有非常高的计算精度，避免了迭代运算，在船舶操纵模拟器中得到广泛应

This invention relates to MIMO test method in a multi-user MIMO radio communication system including: estimating the channel matrixes of all users at the base station, computing an orthogonal projecting matrix M of the interference matrix of each user and transmitting M to each user periodically, receiving data sent by the base station at the user end and getting the orthogonal projecting matrix M from the received data, transforming the MIMO test of a desired user to the minimum value of a K-element secondary convex function, in which, K expresses the number of sending antennas and getting estimation of the test data by a ball test method.

一种多用户多输入多输出无线通信系统中的MIMO检测方法，包括步骤：在基站估计所有用户的信道矩阵；计算每个用户的干扰用户矩阵的正交投影矩阵M，并将每个用户的正交投影矩阵M定期发送给每个用户；在用户端接收基站发送的数据，并从接收的数据中得到正交投影矩阵M；利用正交投影矩阵M将期望用户的MIMO检测转化为K元二次凸函数的极小值，其中K表示对期望用户而言，发送天线的个数；利用球检测的方法，得到检测数据的估计。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。