1. Data acquisition
1.1 What is data acquisition?
Data acquisition (DAQ, DAS for short) is the sampling of the real world to generate data that can be manipulated by a computer.
It consists of acquisition of signals and waveforms and processing the signals to obtain desired information.
1.2 How to acquire data?
Step 1: Set up an object we want to investigate, e.g. an island.
Step 2: Determine which physical phenomenon or physical property of the object investigated will be measured, e.g. temperature or temperature change.
Step 3: Use some sensors (i.e. transducers) to measure.
Step 4: We will get digital/analog signals, i.e. raw signals.
Step 5: Signal conditioning is necessary if the raw signals are not suitable for DAQ hardware.
Step 6: There is a DAQ hardware connected with PC to get the dataset (signals). Also, there is software (e.g. LabView of NI) allows the OS to recognize the DAQ hardware and program to access the signal being read by the hardware.
Step 7: We can use MATLAB to do signals processing.
2. Data Analysis and Data mining
Data analysis is the process of looking at and summarizing data with the intent to extract useful information and develop conclusions.
Data mining tends to focus on larger data sets, with less emphasis on making inference, and often uses data that was originally collected for a different purpose.
3. Data Model
3.1 What is Data Model?
A data model in software engineering is an abstract model that describes how data is represented and accessed.
In database model theory, there are four kinds of data model, i.e. Flat model, Hierarchical model, Network Model and Relational Model. There are many other kinds of data model for different purpose. For example, in Geographic Data Model, some special model proposed to make up 2D and 3D maps.
Also, in WSN, we need to develop a new data-driven model to suit for the limited energy and communication resource.
3.2 How many kinds new Database Management has been proposed for WSN?
(1) Tiny DB from
The Design and Evaluation of a Query Processing Architecture for Sensor Networks
(2) Cougar from
Query Processing for Sensor Networks
(3) DIMESION from
DIMENSIONS: Why do we need a new Data Handling architecture for Sensor Networks?
3.3 What is the relationship between DB Model and Data Acquisition?
In Data Acquisition System, we use hardware to acquire data from sensor networks. Between Step 3 and 4 of last section, we should determine which data should be collected? What kind of model will be used when they acquired by the machine?
Actually, due to the computation ability of WSN nodes, we will pre-process the data before they were acquired by the hardware, i.e. prior to signals.
Reference: http://en.wikipedia.org/wiki/Data_acquisition
http://www.adinstruments.com/products/data-acquisition/corporate/
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