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Sensor Analysis for the Internet of Things [Pehme köide]

While it may be attractive to view sensors as simple transducers which convert physical quantities into electrical signals, the truth of the matter is more complex. The engineer should have a proper understanding of the physics involved in the conversion process, including interactions with other measurable quantities. A deep understanding of these interactions can be leveraged to apply sensor fusion techniques to minimize noise and/or extract additional information from sensor signals.

Advances in microcontroller and MEMS manufacturing, along with improved internet connectivity, have enabled cost-effective wearable and Internet of Things sensor applications. At the same time, machine learning techniques have gone mainstream, so that those same applications can now be more intelligent than ever before. This book explores these topics in the context of a small set of sensor types.

We provide some basic understanding of sensor operation for accelerometers, magnetometers, gyroscopes, and pressure sensors. We show how information from these can be fused to provide estimates of orientation. Then we explore the topics of machine learning and sensor data analytics.
List of Figures
xi
List of Tables
xv
Preface xvii
Acknowledgments xix
Nomenclature xxi
1 Introduction
1(6)
2 Sensors
7(22)
2.1 Accelerometer
8(5)
2.1.1 Accelerometer Placement
11(2)
2.2 Magnetometer
13(10)
2.2.1 Hard and Soft Iron Magnetic Compensation
14(5)
2.2.2 Magnetometer Placement
19(4)
2.3 Gyro Sensor
23(2)
2.4 Pressure Sensor/Altimeters
25(4)
3 Sensor Fusion
29(36)
3.1 Terminolgy
31(6)
3.1.1 Degrees of Freedom (DOF)
31(1)
3.1.2 Axis/Axes
32(1)
3.1.3 Sensor Module Configurations
33(4)
3.2 Basic Quaternion Math
37(3)
3.2.1 Introduction and Basic Properties
37(1)
3.2.2 Equality
38(1)
3.2.3 Addition
39(1)
3.2.4 Multiplication
39(1)
3.2.5 Complex Conjugate
39(1)
3.2.6 Norm
39(1)
3.2.7 Inverse
40(1)
3.3 Orientation Representations
40(11)
3.3.1 Euler Angles and Rotation Matrices
40(4)
3.3.2 Quaternions
44(3)
3.3.3 Conversions between Representations
47(2)
3.3.4 Orientation Representation Comparison
49(2)
3.4 Virtual Gyroscope
51(5)
3.5 Kalman Filtering for Orientation Estimation
56(5)
3.5.1 Introduction to Kalman Filters
56(2)
3.5.2 Kalman filters for Inertial Sensor Fusion
58(3)
3.6 Tools
61(4)
3.6.1 Numerical Analysis
61(1)
3.6.2 Tools to Create Fielded Implementations
62(3)
4 Machine Learning for Sensor Data
65(20)
4.1 Introduction
65(1)
4.2 Sensor Data Acquisition
66(1)
4.2.1 Structured vs. Un-Structured Data
66(1)
4.2.2 Data Quality
67(1)
4.2.3 Inherent Variability
67(1)
4.3 Feature Extraction
67(4)
4.3.1 Time-Domain Features
68(1)
4.3.2 Frequency-Domain Features
68(1)
4.3.3 Time-Frequency Features
69(1)
4.3.4 Dimension Reduction
70(1)
4.3.5 Feature Selection
70(1)
4.4 Supervised Learning
71(5)
4.4.1 Linear Discriminant Analysis
71(3)
4.4.2 Support Vector Machines
74(1)
4.4.3 Kernel Functions
74(2)
4.5 Unsupervised Learning
76(1)
4.6 Remarks---Learning from Sensor Data
77(1)
4.7 Performance Evaluation
77(2)
4.8 Deep Learning
79(1)
4.9 Integration Point of Machine Learning Algorithms
79(2)
4.10 Tools for Machine Learning
81(4)
5 IoT Sensor Applications
85(10)
5.1 Cloud Platforms
85(5)
5.2 Automotive Industry
90(2)
5.3 Unmanned Aerial Vehicles (UAV)
92(2)
5.4 Manufacturing and Processing Industry
94(1)
5.5 Healthcare and Wearables
94(1)
5.6 Smart City and Energy
94(1)
6 Concluding Remarks and Summary
95(2)
Bibliography 97(16)
Authors' Biographies 113