Summary To provide a connection between low earth orbit (LEO) satellite network and terrestrial Internet, a geographical addressing strategy for LEO network is proposed in this paper. When the IP geo‐subnet is divided based on location, the terrestrial users inside and satellite routers above each subnet could be allocated and maintain IP addresses under the regulation of IP network. The addressing strategy is implemented in the first hop and last hop of packet transmission. This paper proves that the application of geo‐subnets could effectively reduce the route table size and generation time in large‐scale space‐ground integrated network as well as maintain the stability of route table when the user condition alters. The performance loss of abnormal addressing caused by the change of satellite coverage would decrease with the reduction of geo‐subnet area. However, the decrease rate would decline during the subnet subdivision and therefore has limited optimization for abnormal addressing. The routing broadcast strategy proposed in this paper could effectively reduce the system packet loss brought by abnormal user at the same geo‐subnet division. Simulation confirms that the geographical addressing strategy combined with routing broadcast optimization in this paper could achieve more than 90% network throughput while reducing 76% of the routing cost.

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In recent years, with the BIM technology application matures in the field of construction engineering in our country，BIM is becoming more and more widely applied in the field of building water supply and drainage design, the effects of it is becoming more and more profound. In view of this, in this paper, the application of BIM technology in building water supply and drainage engineering design, as well as the present problems of the BIM are analyzed.

By using the technology of CAD drawing and standard design calculation is very necessary and feasible. Designers can use the technology of parametric drawing, carries on two times of CAD development of the use of VBA language, the water processing graphics processing and engineering graphics rendering and completed in the computer, realize the parametric design of water treatment structures. Users only need to input the basic parameters that can be completed treatment structure graphics and rendering in CAD, reduce the processing procedure and time complexity. Based on the traditional plug flow aeration tank as an example, introduces the parametric design of traditional plug flow aeration tank by VBA.

As the rapid development of urbanization in China, the conservation of building energy has become a world trend, the rapid rise of building energy will lead a huge pressure on energy supply and environment protection. Renewable energy sources, like solar and geothermal energy, have the incomparable superiority than conventional energy sources, if renewable energy sources could replace conventional energy source and play a major role fully, the serious energy consumption must be relieved effectively. In this thesis, the summer-refrigeration of SWHP (Surface Water Heat Pump) is set as the research target, the applicability research of SWHP is carried out, apart from that, building the evaluation system and putting forward the level determination method of energy efficiency.