## 2 Literature Review
### Smart Home for the Elderly
It aims to help people improve the comfort of the home environment. Second, energy usage optimization. It is to continuously monitor important parameters of the home environment and optimize the energy usage to realize energy saving. Third, emergency and accident prevention. This aspect is to use sensors network to monitor and predict home life and environmental hazards to reduce property and personal accidents. Fourth, healthcare. This function is mainly to help seniors cope with the reduction of physical functionsthrough intelligent technology, like perception and cognitive abilities. Fifth, health management and medical rehabilitation. This aspect is to monitor the elderly's mobility and physiological parameters through wearable biomedical sensors to provide health management and rehabilitation treatment. It is true that the use of intelligent devices and sensor technology is the foundation of a smart home, and health and safety issues are one of the most concerned aspects of the elderly group. However, with unprecedented developments on the medical level, there is an increasing number of healthy elders and this group accounts for a large proportion of the whole elderly population [45]. In terms of spiritual and emotional life, their needs are no different from those of normal people. Older adults want an independent, safe, and decent life, they also need recognition and respect from the external world rather than being treated as a vulnerable group who needs additional help [46].At the same time, the mental status of the elderly plays an important role in their physical health. Even before serious diseases, the psychological state exerts a significant effect on their health status [47]. So the research and developers of a smart home for seniors only laying emphasis on the technical part or home environment or healthcare indeed somehow loses the essence of elderly needs. Because these concerns mostly stay at the survival level and ignore the psychological needs and spiritual life of the elderly group. Some scholars have also noticed related issues and put forward that smart home should promote the socialization interaction of older adults and help them deal with the problem of isolation [29; 48; 49], but they fail to put forward the concept of creating a smart home for all-around happiness for the elderly and lack the in-depth exploration of relevant system construction. This study argues that smart homes for the elderly should break through the traditional definition and impression of \"helping the elderly\" so that the elderly could get rid of the sense of being \"monitored\" and \"served\". The researchers and developers in the field of a smart home for the elderly should see some important phenomena: after the elderly's retirement, they lose their jobs and have increasingly less contact with society and the external world [50]. At the same time, as they get older, old people's physical functions such as perception and sensation have decreased year by year due to the growth of age. The double decline of physical function and social function has caused the separation of the physical and psychological connections of the elderly with the external world [51]. Thus, how to apply modern technology to help the elderly rebuild \"connectivity\" and create an independent, safe, happy home environment to improve their quality of life and all-round wellbeing is a question that all the smart home industry researchers and developers should take into consideration.