Distribution and Rendering of Real-Time Scene Based on the Virtual Reality System - Advances in Image and Graphics Technologies - page 197

for the replacement strategy. The best method is to replace the file video file that will
not be visited in the future. We have calculated the weight of every media file in the
cache server. The file with minimum weight will be replaced. is the visited fre-
quency of the virtual scene in the same zone with real scene. is the number of visits
of the media file. is the time of media file last visited. Based on information of
the visit of the real scene and virtual scene, we have calculated the weight of the me-
dia file.

( 1 )

The edge distribution server that has the smallest load will be selected and returned
in the same subnet with the client when client requests data flow from server. Factors
such as bandwidth, memory, I/O and CPU resources are taken into account for the
content distribution server. However, bandwidth and memory are the two most impor-
tant factors for the pressure from the video streaming distribution system. We have
noticed that ʳ is the load factor to server, which is the sum of bandwidth factor ʱ and
memory factor ʲ . is the total amount of bandwidth of the server and is
the amount of bandwidth used by a client connection. is the total amount of
physical memory of the server and is the amount of memory used by a client con-
nection.

ʴ·ʱ1ʴ·ʲ

( 2 )

ʱ

∑

( 3 )

∑

( 4 )

The content distribution server is dynamically allocated to achieve the load balance
by controlling the memory factor and bandwidth factor. Because the server network
environment, the operating system and other factors, the bandwidth normally take
maximum factor 0.8, the memory factor is 0.6 [13] .One of the minimum load Servers
in the region determined by IP address of client which is returned when client
requests data flow. The server that ʳ is the minimum value is selected. More concur-
rent requests are carried and a steady stream of small delay has been caused by the
strategy.

4 Collection and Rendering

The mobile device can identify the location of the virtual system by its GPS sensor
when during the recording of a real scene. Because of the difference between the vir-
tual scene and the real scene, the automatic calibration has the problem of high error