CHAPTER Embedded IoT Platform Design Methodology Purpose and requirement specification, Process specification, Domain model specification, information model specification, Service specifications, loT level specification, Functional view specification, Operational view specification, Device and component integration, Application development. 24 Introduction — In Chapter 1, we have studied six IoT system levels. Every IoT level starting from oT level 1 to [oT level 6 consist of different components and deployment configurations. — For different application different levels are suitable. — Different components like ToT devices, network resources, application server, database server, web services, analytics components requires interaction between them in IoT system. — So designing loT system is challenging task. Because of various choices available for each component it is very difficult for designers to evaluate among available alternative. = So lof system designers consider specific product or service and design system with respect to that product, or service. Disadvantage of above technique is it may lead to vendor lock-in which may be satisfactory to vendor but totally unacceptable to the customer. - Another disadvantage is adding new feature or replacing certain service or product choice for ‘component is very complex and sometime may require re-design of IoT system. = Inthis unit, we will learn generic design methodology. = Thatis this design methodology will be independent of specific service or product. — This methodology is also independent of programming language. Advantages of using such methodology Design, testing and maintenance time is reduced. ~ Provide better interoperability. ~ Complexity is reduced, 2.2 loT Design Methodology ‘Q. Which are various steps in loT design methodology ? Fig. 22.1: oT system Design Methodology Various steps involved in IoT system design methodology are shown in Fig. 2.2.1. To explain every step in fo system methodology we will consider example of smart [oT based home automation system. Scanned with CamScannerSs Syllabus Topic : Purpose and Requirement = Specification 2.21 Purpose and Requirement Specification Q. Explain purpose and requirement specification in loT ‘design methodology with example, Q. Consider any IoT based application and write purpose 8nd requirement. — This is the first step in design methodology where we define the purpose and requirements of the system. Requirements include various requirements like data collection requirements, system management requirements, data analysis requirements, data privacy requirement, security requirements, user interface requirements. — Considering the example of home automation system, purpose and requirement specification can be described as follows > Purpose Home automation system which will allow controlling ‘f lights in a home with the help of web application. © Behaviour ‘Our system should have auto mode as well as manual ‘mode. In auto mode, system should be capable of measuring the light level in the room and if light level is low (or very ow) then it should switch on the light. In manual mode, system should provide choice of manually operating (on/off) the light. ‘= System Management Requirement JT system for home automation system should have ‘capability of local analysis of data. ¥ (SPPU-Sem 6-Comp) 2-2 Embedded loT Platform Design Methodoion, the second step in IoT design methodoiog, where we define process specifications. Process mode specification for home automation system is shown jg Fig. 2.22. In Fig. 2.2.2, we can see two modes oy system auto mode and manual mode. If mode is aut, mode, the system Keeps track of light level. System changes state of light to on if light level is low (or very low). © seep Omen Fig 2.2.2 : Home automation IoT system process specification — System changes light state to off if light level is high (if there is no need of light). = If mode is manual mode then system checks light level in the room set by the user. If light state is on (i.e. user set light state on) then system changes light state to “on”. If light state is off (i.e. user set light state off then system changes light state to “off”, ——— Syllabus Topic : Domain Model Specification ———_———————— eee 2.2.3 Domain Model Specification Q. Write domain mode! specification for smart home ‘automation system. § [ ~ This is the third step in IoT system desis ~ methodology. In this step domain model is defined. Scanned with CamScannerSPF FRFES KE oft Be 11s 3 | BE emesis ‘and JoT (SPPU -Sem 6 - ~The domain model consists of description about main concepts, entities and objects in the domain of system ‘which is being designed. Domain model also defines various attributes of objects ‘and. relationships between those objects. Abstract representation of main concepts, entities and objects is provided by domain model. This abstract representation isindependent of technology and platform to be used. — With the help of domain model system designer can ‘easily understand the [oT domain for the system which he wants to design. — Fig. 223 shows domain model for our example of hhome automation system. Main concepts, entities and ‘objects in the domain model consist of physical entity, virtual entity devices, resources and services. as = Discrete and identifiable entities like room, light, an appliances are physical entities in the physical ‘environment. = Using sensors or by performing actuation on physical ‘entities, IOT system gives information about various physical entities. = In our example of home automation system two physical entities can be considered. First entity can be room of which light level is monitored and second entity can be light appliance which is to be controlled (on or off). = Representation of physical entities in digital word is called as virtual entity, There is a virtual entity for every physical entity. As there are two physical entities in our example of ‘home automation system there will be two virtual ‘entities one for room and other for light appliance. © Device Physical entities and virtual entities interact with each other through some medium which is provided by devices. Devices can be deployed near physical entities or attached to physical entities. ~ Devices collects information about physical entities for ‘example information can be collected using various sensors. Using actuators devices can perform actuation ‘on physical entities. Devices can also used to identify physical entities using tags. ~ In home automation system devices is minicomputer ‘with light sensor and relay switch (actuator). ) 23 Embedded oT Platform Design Resources are nothing but software components Resources can be “on-device” resources or network- resources. “On - device Resources”: They are hosted on device On-device resources consist of software components that give information on physical entities to which they are attached. They also enable actuation on physical entities. “Network Resources”: Network resources consist of software components that are available in network for example database. In our example of home automation system operating system which runs on single board minicomputer is an “on-device” resource. = Service Interface to interact with physical entity is provided by services. Resources hosted on a device or network resource are accessed by services in order to obtain information about physical entity and perform actuation on physical entities, ‘Now consider our example of home automation system. ‘There are three services which are as follows : (1) Service to set mode (auto or manual) (2) Service to set light state (on or off) or to find out current light state. ) Controller service. Controller service runs as native service on device. In auto mode controller service checks the light level ‘and switches the light ‘on’ or ‘off according to light level. Also updates status in database. In manual mode current light state is retrieved by controller service from database based on the retrieved ‘current state if switches the light “on” or “off” “Syllabus Topic : Information Model Specification 2.24 Information Model Specification = This is the fourth step in the IoT system design mode! where we define information model. Structure of all information like attributes of virtual Entities, relations, ‘tc, is described in information model. It doesn’t explain details about how information is stored or represented. — In order to define the information model, we have to first list the virtual entities. After that by describing their attributes and relations information mode! adds ‘more details to the virtual entity Scanned with CamScanner- 3 embedded 10T Platform Design, Meg, & Embedded Systems and ioT SPU - Sem 6 COMB) ES In our example of home automation system there are two virtual entities. One is virtual entity for light appliance which has attribute light sate Another virtual entity is room which has attribute light level. Information model is shown in Fig. 224, —+ oe way Aasociten —*Aaarepaton formation model of JOT based Dome aitomaton yay i 2.2.5 Service Specifications Scanned with CamScannerET emvosies and IoT (SPPU - Sem 6 - Comp. Embedded loT Platform Design Methodology ‘This is fifth step in design methodology where we define a service specification that is describing various services in IOT system. Service specification includes defining various services in the system, their service types, service inputs and ‘outputs, service endpoints, schedules of services, service preconditions and service effects. For our example of home automation system we have made process specification and designed information model. Fig. 2.2.5 shows derivation of services from [Process specification and information model. Steps of deriving of services from specification and information model are as follows : ‘© Identify states and attributes. (© Define a service for each state and attribute. © That services can find out current values of state ‘or attribute or can change that values. In our example of home automation mode service can retrieve current mode or can change mode from auto to ‘manual or vice versa. In the same way state service can sets the light appliances to on or off or can retrieve its current state. Controller service can monitors the light level and can switch light on or off. Service can also update status to database. If mode is manual mode then controller service can retrieve current state from database and then can switch the light on or off. Fig. 2.2.8 : Controller service specification — Fig. 2.2.6 shows specifications of mode service. Fig. 2.2.7 shows specifications of state service and Fig. 2.2.8 shows the specifications of controller service. ‘Some of the important details about mode service are: = Itis a RESTful web service. = Service can set mode to auto or manual using PUT request. — Service can retrieve current mode using GET request. — Mode is updated to the database or can be retrieved from database by using mode service. Some of the important details about state service are: = Itis also RESTful web service. = Service can set state of light to on or off using PUT request. = Service can retrieve current state using GET request. = State is updated to the status database or can be retrieved from status database, Details about controller service are as follows: ~ Runs as a native service on the device. = If mode is auto mode then this service checks the light level. According to light level service switches the light on or ff and updates the status in the status database. — If mode is manual mode then this service retrieves Current state that is on or off from status database and Switches the light appliance on or off. Syllabus Topic : loT Level Specification 2.2.6 _loT Level Specification ~ We have studied IoT deployment levels in unit ~ 1 Scanned with CamScannerToT deployment levels are @ ToT level - 1. Gi) ToT level -2. Gi) ToT level -3. (iv) ToT level -4. (vi) IoT level -6. () ToT levels, ~ In our example of home automation system we have used [oT level - 1. JoT level ~ 1 based system has a single node or loT device that performs sensing, actuation, data storage, Performs data analysis and hosts the application. As shown in Fig. 2.2.9 a single node is responsible for sensing, storage and data analysis. Cloud Fig. 2.2.9 : Deployment design of home automation system IoT level ~ 1 based solution are used for low-cost low- complexity solutions in which data involved is less and data analysis and computational complexity is low. = In our example of home automation system home appliances(lights) are controlled remoiely via application. — A relay is connected in a system with single node ToT. device and lights and/or other home appliances. — Status information of each connected home appliance is maintained via device monitoring in a local database. = _ REST service is used to access and update the status of lights and appliances by changing the values in local database. ‘The controller service continuously monitors the database and keeps track of the appliances and triggers the relay switches. - The which is deployed locally provides a GUI using which lights and other home appliances can be handled by the user. AS i 25 ‘control the home appliances, ee 7.29 shows deployment desig automation system. rl View Spec, Functional Peciticatiy ‘Syllabus Topic: 227 Functional View Specification ]Eipian funcional view specication stop in (oT dea) ‘diagram mapping of deployment leg Eee eporis extortion aysion. "* | 2, write note on functional 9rOUPS. Pow ‘This is the seventh step in IoT design me methodology where we define functional view Functions of IoT system are grouped into var Functional Groups (FG). We define these functions . ~ oT system in functional view specification. Every FG that is functional group provides differs functionalities which are used for interacting wy instances of concepts which are defined in Doma: model or FG provides information related to they ; concepts. = Functional Groups (FG) consists of : 1. Device functional groups 4 2. Communication functional groups 7 3. Services functional groups Z Management functional groups 6. Security functional groups % ToT system is handled by thes Sommunication protocols, frOups consist of variow ~ These Protocols enable Sonsidered as backbone cp nor Connectivity and can Web aot system. Communica“ Socket are used by services 3 system followin Scanned with CamScanner. Embedded ‘and IoT (SPPU - Sem6-Comp.)_2 Link layer protocol : (802.11) Network layer protocol : Pv4 / IPv6 ‘Transport layer protocol ; TCP Application layer protocol : HTTP = Communication API's are REST based in home automation system. © Service Functional Group This functional group consists of following services = Device monitoring services = Device control services = Device discovery services = Data publishing services = _Inour example of home automation system. ‘There are two REST services. Mode service and state service and one native service that is controller service. © Management Functional Group Functionalities which are required to configure and ‘manage the IoT system are provided by management functional groups. ‘© Security Functional Group JoT system also requires security mechanisms security ‘mechanisms like authentication, authorization and data security are provided by security functional group. Embedded loT Platform Design Methodology ‘© Application Functional Group This functional group consists of applications that provide an interface to the users for controlling and monitoring of various aspects of IoT system. These applications allow users to view processed data as well as system status. = Mapping of deployment level to functional groups For Smart home IoT system mapping of deployment level to functional groups is shown in Fig. 2.2.10. = Devices which include sensors, actuators and communication devices are mapped to Device FG and device management (Management FG). = Resources maps to Communication FG and Device FG. = Controller Service maps to native Service that is to Services FG. = Database maps to database management and database security that means database maps to Management FG ‘and Security FG. — REST web service maps to services FG. — Application maps to web app, application server, database server that is to Application FG. ~ Application also maps to application management and application security that means it maps to Management FG and Security FG. Scanned with CamScannerThis is the eighth steps in JoT desi in IoT design methodology here we define operational view specifications. Options operations which are related to IoT system deployment are defined in this step. ae These options are as follows: = Device options — Storage options ~ Application hosting option = Service hosting option Mapping of functional groups to operational view for JoT based home automation system is shown in Fig. 2.2.11. embedded 1oT Pater pis = Communication Al Ais ‘Communication API ike RES ‘Communication Protocols jon protocols sre — Link layer protocol = wee mae “Transport layer protocol= TCP ‘Applicaton layer protocol HTTP ®& Services Services include mode controller service. © Mode Service It is RESTful web service which is hosted on a device. Service can be implemented using Django-REST framework. > State Service It is RESTful web service which is hosted on a device. ‘Service can be implanted using Django-REST framework. ® Controller Service ice, state service and Controller service is run as native service and it is hosted on device. This service can be implementing in python. = Application Application details can be as follows ~ Web application will be Django Web Application ~ Application server can be Django App Server — Database server can be MySql. © Security z view for | Authentication and authorizati . Fig. 22.11 : Mapping functional groups to operational authorization mechani TOT based home automation system applied to web App and databases —" onal view specifications of home automation | |” yy) system are as follows: x3 - ation management can be done wit @ Devices Djan, with the help of "G0 App Management. Devices consists of — Database management with Computing devices like raspberry Pi ceased the help of Mysql DB sistor Light dependent res! ~ Device management with the Relay switch device management help of Raspberry Pi Scanned with CamScannerEmbedded Systems and IoT (SPU - Sem 6 - Comp.) “Ha Embedded oT Platform Design. ‘Syllabus Topic : Device and Component oP ptegration 2.2.9 Device and Component integration @. Describe device and component integration for loT {Q, Explain in short devices and components which can ‘based home automation system, ‘be used in loT based home automation system. This ninth step in IoT design methodology where we ccan integrate devices and components. Schematic diagram of home automation system is shown in Fig. 2.2.12. ‘Broadboard for connection Fig. 22.12 : Home automation system with sensors and actuator integrated = Devices and components Devices and components which are used in our ‘example are Raspberry P, LDR sensor. Relay switch actuator. Raspberry Pi — The Raspberry Pi is a series of powerful, small single-board computers. The Raspberry Pi is developed by Raspberry Pi Foundation in the United Kingdom, — Various versions of Raspberry Pi have been out Aill date. All versions consist of & Broadcom system on a chip (SoC) with an integrated ARM compatible CPU and on-chip graphics processing unit (GPU). Processor speed of device ranges from 700 MHz {0 1.2 GHz and memory range from 256 MB to 1 GBRAM. = To store the operating system and program memory Secure Digital (SD) cards are used Raspbian OS which is a Debian-based Linux operating system is recommended OS by Raspberry Pi Foundation. Some other third party ‘operating systems like RISC OS Pi.Diet Pi, Kali Linux can also be run on Raspberry Pi. — Fig. 2.2.13 shows Raspberry pi 3 model B. teen Tie He gaye Fig. 22.13 : Raspberry pi3 model B LDR sensor = LDR that is Light Dependent Resistor is a ‘component which has variable resistance. ~ Resistance changes depending on intensity of light falling upon it. This property makes LDR useful in various light sensing circuits — LDR sensor converts light energy into electrical signal output. ~ LDR sensors generates output signal which ‘measures intensity of light. In our example of smart home LDR sensors are ‘used to measure intensity of light in a room. Relay switch Actuator = An actuator is the device which carries out the ‘mechanical movements required for any physical process. ~The most basic control of any device is ability to turn it on or off, Best way to do it is by using switches. ~ Relays are nothing but switches which can be tumed on or off by application of a low voltage across the relay terminals, ~ They are commonly found in automatic control applications as they can control equipment directly ‘through electric signals and does not require physical operation. ~ In our example of Smart home we are relay switch ‘o tum light appliance on or off. Scanned with CamScannertot embedded 1 Specificatio [FF exivedded sytem ind IoT (SPPU - Sem Top ‘Domain Mode! Spec . See = syllabus epectcation for smart hom Syllabus Topic : Application Development —_—_—eSaa=——r 2.2.10 Application Development Q. Explain application development step in loT design methodology for smart home automation system. — This is the last step in IoT design methodology. In this step we develop the IoT application. Fig. 2.2.14 shows ‘web application screenshot for home automation system. ‘Welcome to Smart Home Mote ED Ugh Sate ED Fig. 22.14; Screenshot of home - automation application — Application thas functionality to control the mode as well as light appliance. = In auto mode based on light condition in room system will control light appliance (switch on or switch off). ~ Light intensity is measured by LDR sensors which we have used. If light intensity is low (below specified limit) light appliance will tum on. If light intensity is high (more than specified limit) light appliance will tum off, — If mode selected is manual then user can manually tum light appliance on or off. As the device is connected to the internet, application ‘can remotely control the home appliances. 2.3 Exam Pack (Review Questions) @. Which are various steps in loT design methodology ? piatform Design Methodology Wite som ‘section 2.2:3) Oana yn Son oOo O peler 22.3) ran ee vitual entity in domain. mod ~ (Peter section 22:3) ea Hr govie Resources” and Netwoy Pesources” (Refer sation 2.2.5) tabus Topic : Information Model “apr Specification vn information made application for smart hore fe a ae (Refer section 2.2.4) apaniomation rode speciation for ToT based a e284 pplication. (Refer section 2.24) Syllabus Topie : Service Specifications eiication step in IoT system design oe Refer section 2.2.5) Deserve various services in loT system. (Reter section 22.5) Write service specification for smart home automation system. (Reler section 225) Wite note on : () Mode service (0) State service (il) Controier service (Refer section 2.2.5) Syllabus Topic : loT Level Specification Sate diferent loT deployment levels. Explain loT love semaine grat home auioaion sen (Refer section 2.2) = Syllabus Topic : Functional View Specification © Syllabus Topic : Purpose and Requirement Explain functional view specification step in loT design @. Explain pupose and requirement specication in let | g, fee? ‘design methodology with example. diagram mappir (Refer section 22.1) tonal up fot home saan a Consider any loT based application and write purpose |g, (ler Seaton 2.2.7) ‘and requirement. (Refer section 2.2 1) ‘rg nel on funciona group, @ Syllabus Topic : Process Specification - ‘section 2.2.7) Syllabus Topic : Q. Explain process model specication for home opie : E af Rerstonal View Speciation (Rete secon 222) desig meted, *Pefeaton stop trom oT @. Consider any loT based application and write process % (Roter section 22 ‘model specification for same application. Eola operational view (Reter section 222) home automation syetan’ “Petiication for loT based (Refer section 22) Scanned with CamScanner[BF embecied Systems and loT (SPPU -Sem 6 - Comp) 2-11 ‘© Syllabus Topic : Device and Component Integration @. Describe device and component integration for loT ‘based home automation system, (Refer section 2.2.9) ©. Explain in short devices and components which can be ‘sed in loT based home automation system. (Refer section 2.2.9) re Embedded IoT Platform Design Methodology Q. Write note on : (Raspberry Pi (LDR sensors (i). Actuator (Reter section 22.9) ‘= Syllabus Topic : Application Development Q. Explain application development step in loT design ‘methodology for smart home automation system. (Refer section 2.2.10) goog Scanned with CamScanner