## 2 Smart Homes
### Home Application Areas
#### 2.2.1 Energy Management  
Households use one of the major parts of the world's energy and more than half of the energy consumption in homes comes from electricity [14]. The central task of energy management is to reduce costs for the provision of energy in households and residential building facilities without compromising the user's wellbeing. The functions of the home energy management are: controlling activation/deactivation of home appliances, collecting real-time energy consumption from smart meter and power consumption data from various household appliances, generating and monitoring a dashboard to provide feedback about power usage, providing control menus to control appliances and providing a universal link to the broadband Internet. The overall improvement of a house's energy efficiency is urgent. A need to increase energy efficiency of appliances was identified by many researchers and--amidst numerous approaches to do so--a smart home was deemed as a serious answer to this challenge. Emerging trends, developments and paradigms in smart environments such as Smart Homes are frequently based on smart devices and equipment, such as Smart Meters which can manage and monitor through a network the home energy consumption. The aim of an energy efficiency driven Smart Home is to allow the network elements to dynamically work together and make their resources available, with the intention of reaching a common goal, _i.e._, the energy saving of a house. A few key features that apply to various energy efficiency driven Smart Homes are [15]:  
1. The available node energy, which is frequently limited, _i.e._, a battery supplied nodes, which work with limited amounts of energy. 2. Smart devices and equipment, which are able to offer the opportunity to monitor and to remotely control key features within homes. 3. Decision-support tools designed to assist users in making smarter decisions and based on getting the most out of the benefits gained by the end users when they use energy saving services. It becomes then necessary that at the same time with the energy management challenge, a proper communication protocol between smart devices would regularly improve the system performance. The proposed energy efficiency driven Smart Home systems by the literature are based on task assignment, integration of various physical sensing information and control of various devices. However, they do not concentrate on finding the best communication protocol between devices that would translate to an improvement of the overall system performance [15]. Authors researching this specific topic have diverse views about how improvement of household's energy efficiency can be done, what resources to use and what system architecture to implement. Some make a reference to Smart Home Energy Management Systems (SHEMS)--capable of reducing the total electricity bill for consumers and to simultaneously flatten demand peaks [16] while others call it Home Energy Management System (HEMS) [17]. [PERSON] _et al_. propose a methodology to improve smart home information management by promoting device interoperability, and network collaboration for energy efficiency aims to overcome the main issues of existing Smart Homes by mapping the devices' functions and data, correlating the devices' functions with the smart home actions, and defining what information to send/receive to propose energy-control services [18]. However, since the accidents in power security occur frequently, [PERSON] _et al_., proposed to ensure the security of household electricity appliances, designing a power security system based on stream data mining [19]. [PERSON] and [PERSON] present a smart home energy management system using Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 and ZigBee by integrating diversified physical sensing information and control of various consumer home devices, with the support of active sensor networks having both sensor and actuator components [20; 21].