UNIT-III

IoT Design Methodology

3.1 IoT Design Methodology: Purpose and requirement specification, Process specification,
Domain model specification, Information model specification, Service specification, IoT
level specification, Device and component integration, Functional view specification,
operational view specification, Device and component integration, application
development.

3.2 Logical Designing using programming languages.

3.3 Configuration of hardware platform.

IoT Design Methodology:

Steps involved in IoT System Design Methodology:
1. Purpose and Requirement Specification
2. Process Specification
3. Domain model specification
4. Information Model Specification
5. Service specifications
6. IoT Level Specifications
7. Functional view specification
8. Operational View Specification
9. Device and Component integration
10.Application development

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 Step 1 : Purpose and Requirement Specification:
First step is to define the purpose and requirements of the system. In this step, the system
purpose, behavior and requirements are captured. Requirements can be:

 Data collection requirements

 Data analysis requirements
 System management requirements
 Security requirements
 User interface requirements

For home automation system the purpose and requirements specification is as follows:
A home automation system that allows controlling the lights remotely
Purpose
using a web application
Home automation system should support two modes: auto and manual
Auto: System measures the light level in the room and switches on the
Behavior light when it is dark
Manual: Allows remotely switching lights on and off

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 System
System should provide remote monitoring and control functions
Management
Data
System should perform local analysis of the data
Analysis
Application Application should be deployed locally, but should be accessible
Deployment remotely
Security Should provide basic security like user authentication

Step 2 : Process Specification:

The second step in the IoT design methodology is to define the process specification. In this
step, the use cases of the IoT system are formally described based on and derived from the
purpose and requirement specifications. Figure shows the process diagram for the home
automation system.
 The process diagram shows the two modes of the system - auto and manual.
 In a process diagram, the circle denotes the start of a process, diamond denotes a
decision box and rectangle denotes a state or attribute.
 When the auto mode is chosen, the system monitors the light level. If the light level is
low, the system changes the state of the light to “on”. Whereas, if the light level is high,
the system changes the state of the light to “off”.

 When the manual mode is chosen, the system checks the light state set by the user. If the
light state set by the user is “on”, the system changes the state of light to “on”, whereas, if
the light state set by the user is “off”, the system changes the state of light to “off.

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 Step 3: Domain Model Specification
 The third step in the IoT design methodology is to define the Domain Model. The
domain model describes the main concepts, entities and objects in the domain of IoT
system to be designed.

 The domain model describes the main concepts, entities and objects in the domain of the
IoT system to be designed. Domain model defines the attributes of the objects and

relationships between objects. The domain model is independent of any specific

technology or platform.

 Using domain model, system designers can get an understanding of the IoT domain for
which the system is to be designed. The entities, objects and concepts defined in the
domain model of home automation system include the following:
• The physical identifiable objects in the environment
Physical Entity • IoT system provides information about the physical entity (using
sensors) or performs actuation upon the physical entity
• Virtual entity is a representation of the physical entity in the digital
Virtual Entity world
• For every physical entity there is a virtual entity
• Devices provide a medium for interaction between physical and
virtual entities
Device • Devices are used to gather information from or perform actuation
on physical entities
• Resources are software components which can be either on-device
or network-resources
• On-device resources are hosted on the device and provide sensing
Resource or actuation (eg: operating system)
• Network-resources include software components that are available
on the network (eg: database)
• Services provide an interface for interacting with the physical entity
Service • Services access resources to perform operations on physical entities

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 Step 4:Information Model Specification

 The fourth step in the IoT design methodology is to define the Information Model.
 Information Model defines the structure of all the information in the IoT system,
for example, attributes of Virtual Entities, relations, etc.
 Information model does not describe the specifics of how the information is
represented or stored.
 To define the information model, we first list the Virtual Entities defined in the
Domain Model.
 Information model adds more details to the Virtual Entities by defining their
attributes and relations.

Step 5:Service Specifications

The service specification defines the following:

 Services in the system

 Service types
 Service inputs/output
 Service endpoints
 Service schedules
 Service preconditions
 Service effects

 For each state and attribute in the process specification and information model, we
define a service. Services either change the state of attributes or retrieve their current
values. The service specification for each state in home automation systems are as
shown below:
 The Controller service monitors the light level in auto mode and switches the light
on/off and updates the status in the status database. In manual mode the controller
service, retrieves the current state from the database and switches the light on/off.

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  The Mode service sets mode to auto or manual or retrieves the current mode.

 The State service sets the light appliance state to on/off or retrieves the current light
state.

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 Step 6: loT Level Specficatlon
The sixth step in the IoT design methodology is to define the IoT level for the system.

Step 7:Functional view Specification

The Functional Groups (FG) included in a Functional View include:
 Device: The device FG contains devices for monitoring and control. In the home
automation example. the device FG includes a single board mini-computer, a light
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 sensor and relay switch(actuator).
 Communication: The communication FG handles the communication for the IoT
system. The communication FG includes the communication protocols that form
the backbone of IoT systems and enable network con nectivity.

 The communication FG also includes the communication APis (such as REST and
Web Socket) that are used by the servi.ces and applications to exchange data over
the network.
 Services: The service FG includes various services involved in the IoT system
such as services for device monitoring, device control services, data publishing
services and services for device discovery.
 Management: The management FG includes all functionalities that are needed to
configure and manage the loT system .
 Security: The security FG includes security mechanisms for the IoT system such
asauthentication,authorization, datasecurity,etc.
 Application: The application FG includes applications that provide an interface to
the users to control and monitor various aspects of the IoT system. Applications
also allow users to view the system status and the processed data.

Step 8:Operational View Specification

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 Step 9:Device and Component Integration

In this step the devices like sensors, computing devices and other components are integrated
together. The interconnection of different components Raspberry Pi mini computer, LDR sensorand
relay switch actuator in home automation system is as shown in the figure given below.

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 Step 10:Application Development
Using all the information from previous steps, we will develop the application (code) for
the IoT system. The application interface for home automation system is shown below.

Logical Designing using programming languages.

 Logical design is a high-level design and doesn’t provide any detail.
 Logical design can be textual, graphic, or both.
 The logical design of using Python in IoT is easy enough to develop from the standpoint of an
IoT system architecture. Using modern frameworks for IoT and modern protocols for

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 transferring data from devices, we can effectively build high-performing IoT systems.
 Even if we rewrite some of your code during production to C, C++, or Java to improve
performance, in general, the system will function perfectly in Python.

 Logical Design of any IoT application Flowchart

Common IoT Hardware Platforms:

 Raspberry Pi:
 Arduino (Genuino):
 ESP8266:
 Intel Edison:
 Intel Galileo:
 BeagleBone (BeagleBoard):
 Banana Pi:
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  NodeMCU Dev Kit
 Pycom
 Adafruit
 SparkFun
 Espressif

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