A General Nash Equilibrium Semantic Cache Algorithm in a Sensor Grid Database - Data Management in Cloud, Grid and P2P Systems - page 20

processes queries via the semantic cache; and semantic cache manager, which
calculates the different parameters, and manages the store and replacement of
the semantic cache.
System Parameters: Table 1 gives the parameters that specify the physical
resources of the modeled mobile system. All of the devices move within the
spatial domain according to the random method, a Grid Configuration from
50

2000. We vary the Number of Mobile Devices from 100
to 5000. The Wireless Network Bandwidth is given by Bandwidth, which has
a typical value of 19 . 2 kbps . The Wireless Radius is changing from 10 to 100,
most of time focusing on 100. We set the Maximum Hops to forward a routing
message to 2. This value was chosen by experiment because it attained good
cache effects, but did not incur high additional costs. Database relations, cached
semantic segments and cache maintenance data are all physically stored in pages,
whose size is specified by Server Pages, which is set to 1000000. Client Cache
defines the size of the memory cache at the client side, which is set 10000.
Initially, all of the data are stored in the simulated servers, and no device stores
any data in local storage. During the Simulation Period T , which is changing
from 100 s to 5000 s , the system randomly generates one mobile device to issue
1 query, which is a different type, price, and time, according to the location
of the mobile device, in every time t . We vary the Number of Mobile Devices
from 100 to 5000, which yields a moderate-scale data set [7]. The Speed Range
of the mobile devices is from 1 unit/s to 10 unit/s , including of PERSON and
CAR. Because usually the simulation period T is very long, we choose Step
Time, which is changes from 50 s to 200 s to calculate the relative parameters,
for example: Average Response Time and Average Local/Peer Hit Ratio.

× 100 to 1000 ×

Tabl e 1. Parameters Used in Simulation

Parameter Setting

Grid Configuration 50 × 100 , ..., 1000 × 2000

100 , ..., 1000 Number of Mobile Devices

Wireless Network Bandwidth 19 . 2 kbps

Wireless Radius 10 ,..., 100

Max Hops 2

Speed Range 1 unit/s − 10 unit/s

Simulation Period 100 s, ..., 5000 s

Step Time 50 s, 100 s, ..., 200 s

Client Cache Size 10000

Server Page Size 1000000

Semantic degree 1 , 2 , 3 , 4

Location degree 1 ,..., 10

Here, we introduce one parameters: Semantic degree: (1 , 2 , 3 , 4) means the
query generates a rate of semantics, for example, there are three query types:
Restaurant, Hotel and Parking lots. We consider random to skewed distribu-
tions: