在图形中若于个边(edge)上加上一些值，此数值称为比重( weight ) 。而此图形称为比重图形(Weight Graph ) ，若weight是成本( cost )或距离( distance ) ，则称此图形为网路( Network )。根据Spanning Tree的定义，知一个图形可有许多不同spanning tree ，在network中找出一个具有最小成本( Cost )的Spanning tree ，则此Spanning tree称为最小成本生成树。
上传时间： 2013-12-28
上传用户：Shaikh
matlab有限元网格划分程序 DistMesh is a simple MATLAB code for generation of unstructured triangular and tetrahedral meshes. It was developed by Per-Olof Persson (now at UC Berkeley) and Gilbert Strang in the Department of Mathematics at MIT. A detailed description of the program is provided in our SIAM Review paper, see documentation below. One reason that the code is short and simple is that the geometries are specified by Signed distance Functions. These give the shortest distance from any point in space to the boundary of the domain. The sign is negative inside the region and positive outside. A simple example is the unit circle in 2-D, which has the distance function d=r-1, where r is the distance from the origin. For more complicated geometries the distance function can be computed by interpolation between values on a grid, a common representation for level set methods. For the actual mesh generation, DistMesh uses the Delaunay triangulation routine in MATLAB and tries to optimize the node locations by a force-based smoothing procedure. The topology is regularly updated by Delaunay. The boundary points are only allowed to move tangentially to the boundary by projections using the distance function. This iterative procedure typically results in very well-shaped meshes. Our aim with this code is simplicity, so that everyone can understand the code and modify it according to their needs. The code is not entirely robust (that is, it might not terminate and return a well-shaped mesh), and it is relatively slow. However, our current research shows that these issues can be resolved in an optimized C++ code, and we believe our simple MATLAB code is important for demonstration of the underlying principles. To use the code, simply download it from below and run it from MATLAB. For a quick demonstration, type "meshdemo2d" or "meshdemond". For more details see the documentation.
标签： matlab有限元网格划分程序
上传时间： 2015-08-12
上传用户：凛风拂衣袖
Guided vehicles (GVs) are commonly used for the internal transportation of loads in warehouses, production plants and terminals. These guided vehicles can be routed with a variety of vehicle dispatching rules in an attempt to meet performance criteria such as minimizing the average load waiting times. In this research, we use simulation models of three companies to evaluate the performance of several real-time vehicle dispatching rules, in part described in the literature. It appears that there is a clear difference in average load waiting time between the different dispatching rules in the different environments. Simple rules, based on load and vehicle proximity (distance-based) perform best for all cases. The penalty for this is a relatively high maximum load waiting time. A distance-based rule with time truncation, giving more priority to loads that have to wait longer than a time threshold, appears to yield the best possible overall performance. A rule that particularly considers load-waiting time performs poor overall. We also show that using little pre-arrival information of loads leads to a significant improvement in the performance of the dispatching rules without changing their performance ranking.
标签： Testing and classifying vehicle dispatching rules in three real-world settings
上传时间： 2016-04-01
上传用户：五块钱的油条
A belief function distance metric for orderable sets, Information Fusion 14 (4) (2013) 361–373. 期刊论文
上传时间： 2017-10-12
上传用户：ziyoudexiaod
Ever since ancient times, people continuously have devised new techniques and technologies for communicating their ideas, needs, and desires to others. Thus, many forms of increasingly complex communication systems have appeared over the years. The basic motivations behind each new one were to improve the transmission fidelity so that fewer errors occur in the received message, to increase the transmission capacity of a communication link so that more infor- mation could be sent, or to increase the transmission distance between relay sta- tions so that messages can be sent farther without the need to restore the signal fidelity periodically along its path.
标签： Communications Essentials Optical
上传时间： 2020-05-31
上传用户：shancjb
Ultra-wideband (UWB) technology enables high data-rate short-range communica- tion, in excess of hundredmegabit-per-secondsand up to multi-gigabit-per-seconds, over a wide spectrum of frequencies, while keeping power consumption at low lev- els. This low power operation results in a less-interfering co-existence with other existed communication technologies (e.g., UNII bands). In addition to carrying a huge amount of data over a distance of up to 230 feet at very low power (less than 0.5mW), the UWB signal has the ability to penetrate through the doors and other obstacles that tend to reflect signals at more limited bandwidths and higher power densities.
标签： Silicon-Based Front-Ends RF
上传时间： 2020-06-01
上传用户：shancjb
A wireless communication network can be viewed as a collection of nodes, located in some domain, which can in turn be transmitters or receivers (depending on the network considered, nodes may be mobile users, base stations in a cellular network, access points of a WiFi mesh etc.). At a given time, several nodes transmit simultaneously, each toward its own receiver. Each transmitter–receiver pair requires its own wireless link. The signal received from the link transmitter may be jammed by the signals received from the other transmitters. Even in the simplest model where the signal power radiated from a point decays in an isotropic way with Euclidean distance, the geometry of the locations of the nodes plays a key role since it determines the signal to interference and noise ratio (SINR) at each receiver and hence the possibility of establishing simultaneously this collection of links at a given bit rate. The interference seen by a receiver is the sum of the signal powers received from all transmitters, except its own transmitter.
标签： Stochastic Geometry Networks Wireless Volume and II
上传时间： 2020-06-01
上传用户：shancjb
I love telecommunications. It is powerful and it empowers, with far-reaching consequences. It has demonstrated the potential to transform society and business, and the revolution has only just begun. With the invention of the telephone, human communications and commerce were forever changed: Time and distance began to melt away as a barrier to doing business, keeping in touch with loved ones, and being able to immediately respond to major world events. Through the use of computers and telecommunications networks, humans have been able to extend their powers of thinking, influence, and productivity, just as those in the Industrial Age were able to extend the power of their muscles, or physical self, through use of heavy machinery.
标签： Telecommunications Essentials
上传时间： 2020-06-01
上传用户：shancjb
The dictionary definition of telecommunications is ‘communication over long distance by cable, telegraph, telephone or broadcasting’, but since its initiation over 100yearsagothingshavemovedrapidly.Telecommunicationsisnowaverycomplex industrywithmanydifferentpressures,operatinginahighlydynamic environment.It is best viewed as part of a wider industry known as information and communication technology (ICT). The purpose of this chapter is to explain where telecommunication fits in, to highlight some of the complexities – hopefully to simplify them – and to position the industry in today’s dynamic business environment.
标签： Telecommunications Understanding Business
上传时间： 2020-06-01
上传用户：shancjb
Telecommunications is today widely understood to mean the electrical means of communicating over a distance. The first form of telecommunications was that of the Telegraph, which was invented quite independently in 1837 by two scientists, Wheatstone and Morse. Telegraphy was on a point-to-point unidirectional basis and relied on trained operators to interpret between the spoken or written word and the special signals sent over the telegraph wire. However, the use of telegraphy did greatly enhance the operations of railways and, of course, the dissemination of news and personal messages between towns.
标签： Telecommunications Understanding Networks
上传时间： 2020-06-01
上传用户：shancjb
