方向

In this algorithm, the direction-of-arrival is assumed to be a discrete random variable with a priori probability density function defined on a set of candidate points. Whether or not the secondary sample is required is based on the a posteriori probability distribution of a set of candidate point"s, which can be calculated from the array received signals. And then, the resulting beamformer is a weighted sum of the beamformers pointed at the latest set of point"s, which are combined according to the value of the a posteriori probability for each pointing direction.

在该算法中，期望信号的波达方向被看作是一个定义在若干候选波达方向上的离散随机变量，由阵列接收信号计算出各候选波达方向的后验概率，并将后验概率的分布作为是否需要进行二次采样的判断标准；随后，对各波达方向上的波束成形权值线性加权，便可得到自适应波束成形器，权系数为各候选波达方向的后验概率值。

Sediment from river is not the main source of the Rushan Bay now any more ,which leads to the change of balance of sedimentation power. Sediment will transport because of the drive of hydrodynamic elements in macroscopic view .Direction of suspended load is basicly the same as tidal current .Flood tide makes suspended load transport to tip of the inner Bay and to the Mouth in exterior Bay .The direction of longside sediment transport in two sides of the Mouth mainly focus in the Mouth .Because the coastline along the exterior Bay is very meandering and it belongs to the type of bedrock ,besides some sediment going into the inner Bay ,so actual net sediment discharge rate is less than calculation .It develops an ebb delta out of the Mouth and forms tidal sand ridge ,tidal washing canal ,barrier bar and marine physiognomy ;The result of model simulation disclosures that differences of sediment erosion and siltation between single tidal action and wave-current action are very big .From the analysis of sediment composition、sediment sources and stability of beach and ridge ,this article gets the conclusion that the channel has the possibility to silt ,though the course maybe very slow.

通过分析研究文章得出如下结论：沉积物平面分布与水动力的时空变化存在很好的相关性；口门外发育落潮流三角洲，形成潮流沙脊、潮流冲刷槽、浅滩、拦门沙等水下动力地貌；乳山湾河流来沙已不是湾内泥沙主要来源导致沉积水动力平衡发生改变，宏观上表现在泥沙受水动力驱动发生不断运移；悬沙运移方向与涨潮流方向基本一致，湾内涨潮流带来的悬移质泥沙向湾顶运移，湾外悬移质泥沙主要向口门方向运移；湾口两侧岸段沿岸输沙方向均指向口门方向，由于乳山湾外海岸线曲折，两侧岸段以基岩为主，加之部分泥沙进入湾内，实际净输沙量小于计算值；数值模拟发现潮流单独作用与波流共同作用下泥沙蚀淤模拟差别较大；从沉积物组成、泥沙来源及滩槽稳定性三个方面分析，文章认为研究区存在航道淤积的可能性，但过程相对较慢。

The main job and contribution of this paper are as follows:Based on narrowband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, compute the cross-correlation function of FH signals from multichannels, then we get the cross power spectral density matrixCSDM Secondly, select the hops of FH signals from the CSDM via processing and analyzing the CSDM, meanwhile reduce the influence coming from noise, fixed frequency signal and other interferences; Lastly, estimating the DOA of every hop and according to the DOA, we can separate the hops, get the number of FH signals and their parameters. Propose a new method for designing the threshold in FH signal detection. This method makes it easy to get the threshold by theoretic computing and it can extremely reduce the interference of non-FH signals.Based on broadband signal processing, we propose a new method for FH signal blind detection and blind parameter estimation. Firstly, get the DOA of the signals by wideband spatial spectrum estimation; secondly, separate the signals by spatial filtering using wideband beamformer; Lastly, we propose two methods for FH signal blind detection and blind parameter estimation, one is for several constant hop-rate FH signals whose dwell-time are different and another is for a single FH signal whose hop-rate is alterable.By employing spatial interpolation in broadband signal beamforming, it can reduce the number of antenna elements and corresponding RF modules, A/D converters, etc. It can also eliminate the mutual coupling between antenna elements while getting the narrower main beamwidth and lower sidelobe level.

本文的主要研究工作和贡献如下：●提出了一种基于窄带处理的FH信号盲检测和参数盲估计的实现方法，即首先求出多路信号之间的互相关，进而得到互功率谱密度矩阵，然后通过对CSDM进行对折处理来抑制噪声、定频信号及其他干扰的影响，并将所有属于FH信号的hop(每一跳的驻留时间在时频图上持续的线段)从CSDM中筛选出来，最后用阵列信号处理中的到达方向估计理论在频域中估计出各个hop的方向参数，利用方位信息完成FH信号分离并得到FH信号的数目及其各自的参数集；●提出了一种确定FH信号检测门限的策略，该策略不仅使得检测门限能够通过理论计算得到，而且还显著地抑制了非跳频信号的干扰，从而能有效地检测出FH信号；●提出了一种基于宽带处理的短波FH信号盲检测和参数盲估计的实现方法，即首先利用宽带空间谱测向技术得到接收信号的DOA，然后采用宽带波束形成技术对特定方向进行空间滤波，实现多个信号的分离，最后分别提出了两种FH信号的盲检测和参数盲估计方法，第一种方法适用于空间某个特定方向上存在着几个驻留时间不同的恒跳速FH信号和其他干扰信号的混合信号，第二种方法适用于空间某个特定方向上仅含一个可变跳速的FH信号和噪声的混合信号；●将空间插值的概念和宽带波束形成技术结合起来，提出了一种基于频域处理的宽带恒定束宽的波束形成方法。

The article focuses on the teaching of circuitry,from the basic concept,discusses the direction of the voltage or the electric current in different situations such as Ohm′s law,Kirchhoff′s law,Superposition theorem and so on.

结合在多年的教学，本文针对不同的情况电压和电流的方向做了探讨。1电流电压的实际方向和参考方向习惯上把电流的方向定义为正电荷运动的方向或负电荷运动的相反方向，而把电压的实际方向定义为电位降的方向。

Currently there are l2 faculties 1n the college offering courses in l8 undergraduate programs in medical education which include Clinical medicine,Ophthalmology and Otorhinolaryngology,Neuropsychiatry,Oncology,Pediatrics,Emergency Treatment,Pharmacy, Preventive Medicine,Matemal-child Health,Clinical Laboratory Science,Imaging Medicine,Stomatology,Narcology,Forensic Medicine, Nursing,Medical English,Medical Law,and Biomedical Engineering,and 4 Professional Training Programs which consist of Drug Marketing,Medical Laboratory Equipment Maintaining,Marketing,clinical Medicine and Nursing.

目前，学院下设有5个分院及4部3系19个本科专业和4个专科专业，即临床医学、临床医学专业眼耳鼻喉科学方向、临床医学专业神经精神病学方向、临床医学专业肿瘤学方向、临床医学专业儿科医学方向、临床医学专业急救医学方向、药学、预防医学、预防医学专业妇幼卫生学方向、医学检验、医学影像、口腔医学、麻醉学、法医学、护理学、英语专业医学英语方向、法学专业医事法律方向、生物医学工程等本科专业以及药品营销、医学检验设备维修及营销、临床医学、护理学等专科专业，在校生10000余人。

The projection gradient method will be a possible way to solve the problem that we just get. It has been shown that the projections of the every directions, of which is the boundary point in linear restraint problems, are the possible decent directions, and the projection of negative grads direction is a decent direction. In 1960, Rosen proposed the basic idea of projection gradient methods, and then lots of researchers have been tried to find the convergence of this method. But most of them get the convergence with the condition to amend the convergence itself.

在约束最优化问题的算法中怎样寻找有效的下降方向是构造算法的重要内容，在寻找下降方向方面可行方向法中的投影梯度法有效的解决了下降方向的寻找问题，利用线性约束问题边界点的任意方向在边界上的投影都是可行方向，而负梯度方向的投影就是一个下降方向。60年代初Rosen提出投影梯度法的基本思想，自从Rosen提出该方法以后，对它的收敛性问题不少人进行了研究，但一般都是对算法作出某些修正后才能证明其收敛的，直到最近对Rosen算法本身的收敛性的证明才予以解决。

The device comprises: a conveyer belt; a let-off roller (16) on which the conveyer belt runs and from which the rubber tape is let off; a traverser (21) to move the let-off roller (16) in an X-axis direction parallel to the rotational axis of the object; a radial shifter to move the let-off roller in a Y-axis direction perpendicular to the X-axis direction; a tilter (23) to turn the rotational axis of the let-off roller (16) around a reference axis which is parallel to a Z-axis direction perpendicular to the X-axis direction and Y-axis direction.

所述装置包括：输送带；送出辊，所述输送带在送出辊上行进并且所述橡胶带从送出辊送出；移动台，其沿平行于物体的旋转轴线的X轴方向移动送出辊；径向移位装置，其沿垂直于X轴方向的Y轴方向移动送出辊；倾转装置，用于绕平行于Z轴方向的基准轴线转动送出辊的旋转轴线，所述Z轴方向垂直于X轴方向和Y轴方向。

And the direction query efficiency based on multi-approximate index is compared with that based on taditional external approximation index. 2 The algorithms of nearest neighbor and reverse nearest neighbor about point, line and ploygen based on multi-approximate index are proposed after the virous methods of distance measure are discussed in detail. And the query efficiency of NN and RNN based on multi-approximate index is compared with that based on taditional external approximation index. 3 The basic concept of semi-join and the strategy of distance-direction semi-join are introduced. And the model of distance relationship, direction relationship and the bounding for spatial object are discussed. Then the method is presented about how to implement the query of distance-direction semi-join, and the efficiency of the algorithm based on multi-approximate index is compared with that based on taditional external approximation index.

即：1在方向关系矩阵模型、开域方向模型基础上，讨论了基于多重近似索引下的定性与定量方向检索方法，并通过实验对基于多重近似索引与外部近似索引下的方向检索效率进行了对比分析；2详细讨论了各种距离度量方法，提出了基于多重近似索引下的点、线、面的最邻近查询和反最邻近查询算法，并通过实验对基于多重近似索引与外部近似索引下的最邻近查询和反最邻近查询效率进行比较分析；3介绍了半连接的基本概念，探讨了距离关系、方向关系以及空间对象数量的约束模型，给出了基于多重近似索引下的距离方向半连接实现方法，并通过实验对基于多重近似索引与外部近似索引下的距离方向半连接的效率进行了比较分析。

We performed a simulative test, which confirms that wavelet analysis can separate annual wobble and Chandler wobble. Our results show that this method can be used in astronomical geodynamies effectively. This paper is divided into two parts. The first is about statistic characteristic of polar motion. Polar motion includes secular motion, long period fluctuations, Chandler wobble, annual wobble and high frequency wobble. The secular motion is 3.4mas/year and towards 760W meridian. Long period fluctuations have difference periods in x-axis and y-axis. They are 31.7-year and 24-year in x-axis and 28.5-year and 22.9-year in y-axis. These 2~? decades fluctuations have an amplitude of about 30 mas , and are very nearly linearly polarized, with the observed motion of pole being almost entirely along a line between 360E and 1440W. There is a 55.4-year wobble whose amplitude is 9 mas. The amplitude of the interannual fluctuations is about 4? mas. The amplitude of long period fluctuations decreased after 1970. The annual wobble is a steady wobble. It retrograde wobble is only 1/20 of prograde wobble in amplitude.

本文的工作主要分为两部分：第一部分是通过分析POLE97序列，我们对极移的统计特性有了一个较全面的认识，极移主要包括趋势项、长周期项、Chandler项、周年项和高频项：趋势项的方向是西经76°，速度为每年3.4mas；长周期项中Markowitz 项在X、Y两个方向有不同的周期，它们分别是：X方向的两个周期是31.7年和24 年，Y方向的两个周期为28.5年和22.9年它们叠加在一起是一个线偏振运动，最大振幅约为30mas，偏振方向在西经144°和东经36°之间；极移的长周期波动中还存在一个 55.4年周期的圆周运动，振幅约为9mas；十年尺度变化的振幅在4～6mas之间，在Y 方向十年尺度的成份比较多，它们的周期在X方向和Y方向不是对应的；从七十年代年开始长周期变化的振幅明显降低；周年项是一个振幅稳定的摆动，在X、Y两个方向的振幅略有差别，逆向运动振幅大约为顺向运动振幅的1/20；Chandler摆动的振幅自1900年以来经历了几次较大的变化，其中包括1915年和1955年两次极大值，振幅分别达到0&。25和0&。28，以及1925～1940期间小于0.09的过程，Chandler项在X、Y 两个方向的振幅几乎完全相等，其逆向运动振幅不到顺向运动振幅的1/50。

In this study, six campaigns around Anping tide gauge, Tainan, were successfully performed and the collected GPS buoy data were processed with four types of precise ephemeris provided by IGS, including final product, rapid product, ultra-rapid product and ultra-rapid product with the use of PPP technique. Comparing the PPP results with DGPS, the differences reach 3~5 cm in the horizontal and 10 cm in the vertical with final product; 6~8 cm in the horizontal and 15 cm in the vertical with rapid product; 15~20 cm in the horizontal and 30~40 cm in the vertical with ultra-rapid product; 2~3 m in the horizontal and 3~4 m in the vertical with ultra-rapid product. In addition, the collected data were also processed by DGPS techniques using different reference stations to analyze the effect of various baselines. The results show that accuracy degrades when the baselines increase.

本研究在台南安平潮位站旁进行6次GPS浮标施测，首先利用与GPS浮标距离不同之GPS参考主站来进行差分定位，分析基线距离对GPS浮标定位成果的影响，由实验结果可得出基线越长则定位准确度越低；再以IGS提供之最终产品、快速产品、超快速产品(Ultra-Rapid product)之观测部分observed half、超快速产品(Ultra-Rapid product)之预估部分四种不同发布延迟时间的精密星历与精密时表改正资料对GPS浮标进行精密单点定位解算，与传统差分相对定位方法定位结果进行比较后，得出使用最终产品之平面方向均方根误差(Root Mean Square Error， RMSE)可达3~5公分，而高程方向均方根误差可达10公分；快速产品之平面方向均方根误差可达6~8公分，而高程方向均方根误差可达15公分；超快速产品观测部分之平面方向均方根误差可达15~20公分，而高程方向均方根误差可达30~40公分；超快速产品预估部分之平面方向均方根误差可达2~3公尺，而高程方向均方根误差可达3~4公尺。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。