Algorithm 1 Self-adaptive thread sleep-wake (S-ATS-W) algorithm, which is used to rapidly responds to commands to change the frequency with which sensor data is transmitted

Input: database connection string connectionString sensor identification sensorid

Output: void

Use: GetSqlConnection(connectionString) to get a database connection object using the given connection string

CloseSqlConnection(conn) to close the database connection that connection object conn holds to release database resource

GetTransIntervalBySensorID(conn, sensorID) to get sensor data transmission interval from database

GetQueryDBIntervalFromCfg() to get database query interval from external configuration file

ATST(transInterval, queryDBInterval, sleptTime, connectionString, sensorid) algorithm defined thereafter to dynamically adjust the length of sleep time of a thread

Declare: SqlConnectionObject conn

Begin:

1: conn = GetSqlConnection(connectionString)

2: If (conn! = null) then

3:{double transInterval = GetTransIntervalBySensorID (conn, sensorid); CloseSqlConnection(conn);

4: double queryDBInterval = GetQueryDBIntervalFromCfg();

5: ATST(transInterval, queryDBInterval, 0, connectionString, sensorid)}

6: End if

End