A structured mesh is defined as one where each interior node on a surface/volume is connected to 4/6 other nodes. Mappable surfaces contain four logical sides and four logical corners of the map; each side can be composed of one or several geometric curves. Similarly, mappable volumes have six logical sides and eight logical corners; each side can consist of one or several geometric surfaces. For example, in Figure 1 below, the logical corners selected by the algorithm are indicated by arrows. Between these vertices the logical sides are defined; these sides are described in Table 1.
Interval divisions on opposite sides of the logical rectangle are matched to produce the mesh shown in the right portion of Figure 1. (i.e. The number of intervals on logical side 1 is equated to the number of intervals on logical side 3). The process is similar for volume mapping except that a logical hexahedron is formed from eight vertices. Note that the corners for both surface and volume mapping can be placed on curves rather than vertices; this allows mapping surfaces and volumes with less than four and eight vertices, respectively. For example, the mapped quarter cylinder shown in Figure 2 has only five surfaces.
Mapona volume 2
The vop command editsvolume data to create a new volume data set.The original map is undisplayed and the new mapis displayed with the same threshold and color as the original.Map display can be adjustedand the map saved to a file using Volume Vieweror the command volume.See also: mask,sop,Volume Filter,Volume Eraser,Segment Map
The morph is created as a new map (volume) model. However, if the modelId of an existing morph map is given,the new calculation will reuse the memory already allocated to that map,and the size of the input maps must match that of the existing map.Settings and properties other than map size are not retained and must bespecified anew in the command.
The factors affecting road noise emissions include traffic volume,road speed, and road surface materials. Among them, road surface materialsare inherent attributes of roads, and good road surface materials caneffectively reduce road noise emissions [29,30].This paper is based onChina's road environment. China's roads are basically asphaltpavements, so the impact of pavement materials as a fixed item is notreflected in the model parameters. As a result, the acoustical power of roadis calculated using (1) and (2):
where [L.sub.eqi] is equivalent sound level of the ith typetraffic flow to the receiver point without shelter, [L.sub.eq] is Equivalentsound level of the road to the receiver point without shelter, [L.sub.oi] isaverage sound level of the ith type traffic flow to the reference point,[N.sub.i] is traffic flow volume of the ith type traffic flow, [V.sub.i] isaverage speed of the ith type traffic flow, T is the prediction time,[r.sub.0] is distance between the reference point and the lane ([r.sub.0] =7.5m), r is distance between the receiver point and the lane, and [psi] isthe field angle formed by the receiver point, the origin point of the road,and the end point of the road, with the peak of the angle being the receiverpoint.
5.1. Real-Time Traffic Data. There are many taxis in every city,the tracking information of which is owned by those taxi enterprises. Thisinformation is available in real-time. In this study, the traffic data usedto predict noise are calculated from the tracking information of almost 20000taxis in Guangzhou. The instantaneous speed of the taxi is inferred from thereal-time location information of the taxi; then, the speed of each taxi onthe same road over one hour is averaged to obtain the hourly average speed ofthe road. Studies have shown that road traffic volume and average road speedhave different degrees of influence on traffic noise, and there is a clearcorrelation between them [34]. To obtain the hourly traffic volume, largeamounts of traffic monitor video are used to determine the pattern betweenthe road speed and the road traffic volume for different road types, and thehour traffic volume is determined from the hourly average speed. Figure 5shows the taxi tracking data in Guangzhou, as visualized by a GIS tool.Through this method, real-time traffic data does not need to be obtainedthrough all-day traffic monitoring, and traffic data of the entire city canbe obtained; accordingly, this method is not precise enough to obtain trafficdata with high accuracy. 2ff7e9595c
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