WSO2 CEP中Kalman Filter的输入输出参数是什么意思？

Question

我想了解一些关于 WSO2 CEP 4.2.0 中 Kalman Filter Extension 的输入（名称：measuredValue、measuredChangingRate、measurementNoiseSD 和时间戳）和输出（2 个值）的信息。我找不到任何类型的文档。我假设 measuredValue 是要过滤的值，时间戳是关于获取 measuredValue 的时刻的数字标签；关于 measuredChangingRate 和 measurementNoiseSD？此外，我注意到一个问题：当我尝试使用此功能时，Siddhi 说：

No extension exist for StreamFunctionExtension{namespace='kf'} in execution plan "ExecutionPlan"

kalmanFilter函数可能没有任何扩展吗？

我的片段查询是：

@Import('InputStream:1.0.0')
define stream InStream (energy double, timestamp long);

define stream ResKalmanFilterStream (energyEstimated double, x double);

from InStream#kf:kalmanFilter(energy)
select *
insert into ResKalmanFilterStream;

Answer 1

关于以下错误：

No extension exist for StreamFunctionExtension{namespace='kf'} in execution plan "ExecutionPlan"

kf:kalmanFilter(energy) 是一个将属性（在本例中为 energy）作为参数并输出新值的函数。换句话说，它产生了一个新属性，因此必须在 select 语句中使用它。

from InStream
select kf:kalmanFilter(energy) as filteredEnergy
insert into ResKalmanFilterStream;

关于参数；我可以在 Kalman Filter extension source code (refer the class-level comment) 中找到有关参数的以下信息。

measuredValue - measured value eg:40.695881

measuredChangingRate - Changing rate. eg: Velocity of the point which describes from measured value - 0.003d meters per second

measurementNoiseSD - standard deviation of the noise. eg: 0.01

timestamp - the timestamp at the measured time eg: 1445234861l

WSO2 CEP中Kalman Filter的输入输出参数是什么意思？

What is the meanings of the input and output parameters of Kalman Filter in WSO2 CEP?

kalman-filter

wso2cep