You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: A systematic literature review on activity recognition with context-awareness techniques for mitigation of disasters 
Chapter Title:  Problem background 
1. Abstract of Cited Paper (BIB001):  Many researches have indicated that the wireless technology can enhance the learning performance of teaching, learning and self-study. Therefore, the web-based learning has been evolved into mobile learning and even ubiquitous learning in recent years. Certainly, performing language teaching and learning actions by handheld devices in cooperating with advanced wireless technology has been a novel trend. Therefore, the research proposes a context-aware ubiquitous English learning system in a campus environment, which can detect the learner location by wireless positioning techniques, then retrieve specific learning content based on location information to individual learners through wireless networks. Currently, the system prototype has been successfully implemented on PDA and it has been applied to assist English situated learning for learning performance promotion in a campus environment. 
2. Abstract of Cited Paper (BIB002):  The expenditure telecom operators made to prepare themselves for the 3G (and beyond) environment are far from being re-earned and recent research has showed that mobile customers are not willing to spend more money on mobile communication. The telecom industry needs to search for new sources of revenue. Opportunities can be found in the area of context awareness. As location based services are taking off, telecom operators need to understand quickly the possible roles they can play in context aware services before other players in the industry do. Based on a research on context aware services this paper proposes some new business roles interesting fortelco's.

Literature Review:
Previous studies focus on the use of close circuit television (CCTV), as far back as 1995 , video camera in computer vision  , for monitoring people in the crowd to provide safety measure, in the case of unforeseen incidents. These techniques suffer from: 1 no feedback to the potential victims of danger 2 the device which is normal position in a specific location due to their static nature 3 devices are hardly found among people except in rear cases like smartphone. Wireless sensor network was remarked to be suitable for better situational awareness of crowd monitoring in a crowded area BIB001 . Despite this, it has limitations such as: 1 high false negative alarm (FNA) 2 low sensor quality for crowd behaviour recognition. Presently, the research has shifted to the use of context-awareness computing and wireless sensor network BIB002 . Because of the evolution of smartphone sensing and the power of inbuilt sensors with the tendency to monitor and sensitise potential victims of danger for any unforeseen incidents that can cause a disaster during an emergency with feedback to reduce risk associated with such occurrences. Figure 1 depicts the overview of scenarios based on the issues that led to existing studies BIB003  ) that led to the existing studies.