Nowadays, increasing energy efficiency is used to face the great world challenges, such as energy security, air pollution, climate change, and economic crises, among others. Energy efficiency alternatives have the power to optimize energy consumption and reduce greenhouse gas emissions, thus contributing positively to the preservation of natural ecosystems and human health. Additionally, energy efficiency alternatives help mitigate the economic effects in the workplace. For this reason, organizations and governments worldwide are proposing actions for energy conservation with the purpose of reducing energy-related inconveniences. The residential sector is attributed a high energy consumption; however, home automation systems (HAS), combined with IoT, are alternatives that promise to contribute to greater energy efficiency
Likewise, advances in energy conversion, communication, and information technologies have paved the way for a new generation of homes—smart homes—thus allowing people to improve aspects of their houses, such as comfort, convenience, safety, and entertainment, while simultaneously helping them to cut energy waste. Additionally, Home Energy Management Systems (HEMS) are important in achieving the goals of smart energy homes in many countries. Likewise, the smart home market is growing rapidly. In particular, it is improving in areas such as fire detection, lighting, entertainment, and energy efficiency systems, among others. In addition, in recent years, energy conservation action plans for the residential sector have gained prominence, since they contemplate indoor comfort and energy efficiency. In this sense, it is worth mentioning that user behavior patterns in terms of energy consumption change according to user needs and lifestyles, yet there is always an inclination to maintain indoor comfort at the expense of power-saving. Therefore, to design and implement effective energy-saving action plans, it is important to know not only the link between indoor comfort and energy consumption but also home characteristics and home resident needs.
Materials and Methods
Home automation is a component of the appliance domain IoT personal and social and thus offers many opportunities for developing new useful applications. Home automation refers to a set of techniques aimed toward automating a home, which integrates technology into security, energy management, and welfare. Comfort is essential in a home automation system and comprises all the actions performed to improve the way home residents feel in their houses. However, home automation applied within the IoT faces a serious challenge—few communication systems ensure device interconnectivity. This problem arises from the lack of unified protocols and the many different lifestyles of users coexisting in smart cities.
HEMS IoT is a home vitality the executive's framework that looks to add to the solace and
security of smart homes, while simultaneously helping residents save energy. To this end, HEMS-IoT utilizes IoT gadgets, huge information advancements, and AI to oversee vitality utilization. Also, HEMS-IoT allows for the real-time monitoring of domotic devices and home sensors. All the information obtained is analyzed and processed using machine learning algorithms to learn energy consumption patterns and user behavior patterns and make relevant recommendations for cutting energy waste.
HEMS-IoT: Architecture and Functionality
HEMS-IoT has seven-layered engineering, which encourages the framework's upkeep and allows for high scalability. The architecture of HEMS-IoT is presented and integrates the presentation
of the IoT services layer, the security layer, the management layer, the communication layer, the data layer, and the device layer. Every layer has a clearly defined function and includes multiple components having a specific functionality within their corresponding layer.
Presentation layer. This layer ensures bonding between the user and the system through the Presentation layer. This layer ensures bonding between the user and the system through either a mobile application or a web application. At the presentation layer, users can visualize energy consumption data, available IoT services, power consumption history, and recommendations. As a web application, HEMS-IoT receives information and allows users to manipulate and control domotic devices through various devices. As a mobile application, HEMS-IoT works on the Android operating system for users to manage and control domotic devices. In addition, with the mobile application, users monitor home domotic devices, incorporate new rooms, remove or add domotic devices from a particular room in the house and obtain energy-saving recommendations. The application also displays charts to consult energy consumption patterns on a daily, weekly, and monthly basis and offers users energy-saving recommendations for their smart homes.
Security layer. This layer guarantees information security and hence guarantees the confidentiality and secure collection of data from the device layer. Communication between the device layer and the security layer is not direct since they communicate through the communication layer and the management layer.
IoT services layer. This layer serves as a link between the application layer and the management layer. Additionally, this layer provides various REST services, allowing users to fully exploit the functionalities of HEMS-IoT.
Management layer. This layer performs and manages the actions to meet user requirements requested at the application layer. To this end, the IoT layer uses the REST API to ensure communication between the presentation layer and the management layer.
Data layer. This layer saves the data generated in the device layer. Namely, the data layer relies on modules to manage five types of information: recommendations, service profiles, sensed data, device profiles, and user profiles. The recommendations module is responsible for managing comfort and energy-saving recommendations. In turn, the service profile manages data on the provision of system services. The sensed data module saves and manages all the information collected by the device layer from the smart home, such as gas/water/energy consumption and room temperature, among others. The device profile module handles data on domotic devices, such as their status and location, among others. Finally, the user profile module manages user information, such as a full address, name, and gender, among others.
Communication layer. This layer considers elements such as a set of sensors, HTTP and TCP/IP, and 4G communication to establish the communication protocols for each domotic device. Other layers in the architecture communicate with each other through the communication layer.
Device layer. This layer facilitates data linkage and reception from various domotic devices. Also, the device layer controls the actuators and home automation devices. The following subsections describe the most important aspects of HEMS-IoT.
An efficient home energy-saving system must take into account resident preferences in order to successfully control how domotic devices operate in the house. However, home energy consumption also depends on other factors, such as external environment, natural ventilation, temperature variations through seasons, and the age of residents, to name but a few. A few instances of the gadgets considered in the gadget layer of HEMS-IoT are recorded as follows:
Gateways. These objects allow smart home automation devices to remain interconnected. Likewise, gateways are the link between external networks and domotic devices installed in the smart home and make it easier to control domotic devices both remotely and locally. The gateways used in smart homes are border devices that allow access between external and local networks within a house. Because the different home automation devices linked to the smart home connect to other networks or even the Internet, gateways handle the main communication access between those networks.
Sensors. They collect data on different parameters of the smart home, such as the risk of burglary, gas or water leaks, and room temperature, among others.
Actuators. They are usually of various types and are installed throughout the house. Actuators are used to change the status of domotic devices and some home facilities. For instance, actuators can interrupt the water and gas supply, issue failure or risk warnings, increase or decrease the temperature from air conditioners, or adjust light intensity from smart bulbs.
Controllers. These devices allow users to control domotic devices with respect to the chosen parameters. HEMS-IoT recovers information from the different sensors introduced in a house and procedures the information by methods for a calculation. Then, the system prepares the rules necessary to invoke the actuators. Likewise, HEMS-IoT allows users to monitor the status of the operating domotic devices, thus making home residents completely involved in the process. Users can also control and program the actuators and sensors installed in the smart house through a centralized control system and using a touch screen, a keyboard, or a voice interface, among others.
Home needs vary across smart homes, yet the most common include indoor cooling or heating, hot water, and lighting. HEMS-IoT needs to draw upon on reliable communication networks to successfully retrieve energy consumption data and user behavior data. Some of the protocols used in the communication layer of HEMS-IoT are listed below:
ZigBee. The ZigBee Alliance developed the ZigBee protocol following the IEEE802.15.4, a low-power wireless network standard. ZigBee is a low-cost and high-level protocol used to establish personal networks through reduced, low-power digital radios that send information wirelessly to larger areas. In addition, ZigBee is used in low information rate applications that require secure networking and long battery life. Finally, ZigBee considers various kinds of network topologies, including the tree, star, and mesh topologies.
TCP/IP. The US Department of Defense developed the Transfer Control Protocol/Internet Protocol (TCP/IP) with the purpose of intercommunicating computers with various operating systems (minicomputers, PCs, and central computers), which work in local area networks (LAN) or wide area networks (WAN). The TCP/IP protocol is a group of protocols that determine various premises and rules for machines from different providers to exchange data through public telephone networks, such as WAN and LAN networks. Internet design is based on the TCP/IP protocol.
HTTP/IP. The World Wide Web Consortium (W3C) and the Internet Engineering Task Force (IETF) developed the Hypertext Transfer Protocol (HTTP), which is used in any type of transaction made over the Internet. HTTP helps to define the semantics and syntax used by various agents (servers, clients, and proxy) to communicate among them. HTTP is a request-response-client-server protocol, where the HTTP user sends a request to an HTTP server; then, the server returns the message with a response. User requirements include programs, translations, files, and database queries, among others. All the data executed on the Web through HTTP are identified with either an HTTP address or a uniform resource locator (URL).
The communication layer helps home residents control smart home devices, both intelligently and efficiently. The goal in this layer is to collect information from the different IoT-based devices installed in a smart home. These data provide information on the home, such as energy consumption, room temperature, motion, and the air conditioner’s temperature, to name but a few.
sensors are a key element in smart home monitoring. By collecting real-time information, sensors allow HEMS-IoT to analyze and identify how much power smart home appliances and devices are consuming. Users can visualize and monitor this information on a daily basis to make the necessary energy-saving adjustments. Also, thanks to sensors, HEMS-IoT can issue appropriate energy-saving recommendations and invoke both basic services (e.g., plumbing and electrical repairs) and emergency services (e.g., police, firefighters) when required.
This layer uses machine learning and big data storage technologies to easily manage and analyze the information collected in the device layer. Similarly, information access commands are encapsulated by the management layer to ensure information security. The management layer also identifies user behavior patterns and classifies homes according to their energy consumption patterns using the API of Weka 3.8, which is the stable version of the open-source software and successfully helps HEMS-IoT comply with the required functionalities. To classify data and generate energy-saving recommendations, HEMS-IoT uses an open-source Java implementation of algorithm C4.5, which is the J48 machine learning algorithm. C4.5 and J48 are used to generate decision trees, and they are classification algorithms. Classification algorithms are widely used in healthcare and have proved to yield outstanding results in the diagnosis of hepatitis, cancer, heart disease, eye diseases, and tumors on digital mammograms. In addition, J48 has a better performance than other algorithms, such as random forest, CART, random tree, fuzzy C-means, and REPTree.
HEMS-IoT was developed and implemented in a modular and generic way, with better application extensibility, ease of implementation, and with a view to high performance. The tasks performed by the management layer can be divided into four groups:
- User management. Comprises actions such as deleting and editing user-profiles and user registration, among others.
- Home management. Encompasses actions of knowledge deletion, data editing, and management of domotic devices, among others. To this end, we used a subversion of the online ontology language (OWL), the OWL-DL, which is predicated on the SHI2 description logic. Likewise, OWL-DL has a broad vocabulary and greater expressiveness than RDFS. depicts a fragment of the developed ontology, which presents the main domotic concepts, such as home activity, environment, entity, and stay, among others. We also followed the Methontology method to develop the house automation ontology.
- Recommender system.This system issues recommendation for energy-saving and home comfort based on home residents’ behavioral patterns. To this end, the system takes into account both daily and average energy consumption values from each domotic device, which allows the system to generate the rules in the algorithm. Therefore, smart homes are classified on a daily basis with respect to four energy consumption categories: normal, low, medium, and high.
This layer provides various REST-based web services to communicate with both the application layer and the management layer. Therefore, HEMS-IoT clients can without much of a stretch interface with the framework's functionalities. The main components in this layer are described below:
- REST API. REST collects information or performs operations on such information in all possible formats, such as JSON and XML, using HTTP. REST is a good option if compared to other protocols for information exchange, such as the Simple Object Access Protocol (SOAP), which has a high capacity but is a complicated Smart Home System for Energy Saving.
- Service selector. This module validates the parameters passed on by the presentation layer and choosing the required services. Likewise, the service selector has the power to either give or deny services, according to the authentication data and received parameters
This layer guarantees data confidentiality and can retrieve data protected by both the device layer and the end-users. The communication layer and the administration layer facilitate communication between the security layer and the device layer. This layer considers two security components, authorization, and authentication, described below:
- Authentication. This refers to the act of validating with evidence that something/someone is what/who they claim to be. Object/device authentication involves ensuring its origin, whereas confirming user identity usually implies user authentication. In HEMS-IoT, user authentication requires ensuring that the user who wishes to interact with the system is truly who he/she claims to be. When this is the case, HEMS-IoT authorizes said user to access the Smart Home System for Energy Saving.
- Authorization. This occurs after user identity is authenticated by the system. The goal of authorization mechanisms is to protect user information and prevent unauthorized or unidentified users from accessing data or performing particular tasks. Authorization and authentication are different since authorization involves the tasks that users are allowed to perform or the information that can access once their identity is confirmed. User authorization is applied either to individual elements or to a set of them. In smart home management systems, each element relates to an activity to be run.
As a mobile application, HEMS-IoT works on the Android operating system. Figure 4a illustrates the application’s menu list on the presentation layer. The main menu options include home (i.e., return to the initial screen), favorites (rapidly access preferred rooms), statistics (visualize energy consumption patterns), rooms (view homerooms), and devices (visualize domotic devices and sensors connected to the smart home). Additionally, the application’s menu allows users to add and remove devices or rooms, view existing user profiles, consult and change application settings, and exit the application. illustrates samples of comfort, safety, and energy-saving recommendations issued by HEMS-IoT.